<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `apps/ltn/src/partition.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>partition.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled><link rel="stylesheet" type="text/css" href="../../dark.css" disabled><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script src="../../crates.js"></script><script defer src="../../main.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script>
    <noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">&#9776;</button><a class="sidebar-logo" href="../../ltn/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div>
        </a><h2 class="location"></h2>
    </nav>
    <nav class="sidebar"><a class="sidebar-logo" href="../../ltn/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div>
        </a></nav><main><div class="width-limiter"><div class="sub-container"><a class="sub-logo-container" href="../../ltn/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><nav class="sub"><div class="theme-picker hidden"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu" title="themes"><img width="22" height="22" alt="Pick another theme!" src="../../brush.svg"></button><div id="theme-choices" role="menu"></div></div><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><button type="button" id="help-button" title="help">?</button><a id="settings-menu" href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></form></nav></div><section id="main-content" class="content"><div class="example-wrap"><pre class="line-numbers"><span id="1">  1</span>
<span id="2">  2</span>
<span id="3">  3</span>
<span id="4">  4</span>
<span id="5">  5</span>
<span id="6">  6</span>
<span id="7">  7</span>
<span id="8">  8</span>
<span id="9">  9</span>
<span id="10"> 10</span>
<span id="11"> 11</span>
<span id="12"> 12</span>
<span id="13"> 13</span>
<span id="14"> 14</span>
<span id="15"> 15</span>
<span id="16"> 16</span>
<span id="17"> 17</span>
<span id="18"> 18</span>
<span id="19"> 19</span>
<span id="20"> 20</span>
<span id="21"> 21</span>
<span id="22"> 22</span>
<span id="23"> 23</span>
<span id="24"> 24</span>
<span id="25"> 25</span>
<span id="26"> 26</span>
<span id="27"> 27</span>
<span id="28"> 28</span>
<span id="29"> 29</span>
<span id="30"> 30</span>
<span id="31"> 31</span>
<span id="32"> 32</span>
<span id="33"> 33</span>
<span id="34"> 34</span>
<span id="35"> 35</span>
<span id="36"> 36</span>
<span id="37"> 37</span>
<span id="38"> 38</span>
<span id="39"> 39</span>
<span id="40"> 40</span>
<span id="41"> 41</span>
<span id="42"> 42</span>
<span id="43"> 43</span>
<span id="44"> 44</span>
<span id="45"> 45</span>
<span id="46"> 46</span>
<span id="47"> 47</span>
<span id="48"> 48</span>
<span id="49"> 49</span>
<span id="50"> 50</span>
<span id="51"> 51</span>
<span id="52"> 52</span>
<span id="53"> 53</span>
<span id="54"> 54</span>
<span id="55"> 55</span>
<span id="56"> 56</span>
<span id="57"> 57</span>
<span id="58"> 58</span>
<span id="59"> 59</span>
<span id="60"> 60</span>
<span id="61"> 61</span>
<span id="62"> 62</span>
<span id="63"> 63</span>
<span id="64"> 64</span>
<span id="65"> 65</span>
<span id="66"> 66</span>
<span id="67"> 67</span>
<span id="68"> 68</span>
<span id="69"> 69</span>
<span id="70"> 70</span>
<span id="71"> 71</span>
<span id="72"> 72</span>
<span id="73"> 73</span>
<span id="74"> 74</span>
<span id="75"> 75</span>
<span id="76"> 76</span>
<span id="77"> 77</span>
<span id="78"> 78</span>
<span id="79"> 79</span>
<span id="80"> 80</span>
<span id="81"> 81</span>
<span id="82"> 82</span>
<span id="83"> 83</span>
<span id="84"> 84</span>
<span id="85"> 85</span>
<span id="86"> 86</span>
<span id="87"> 87</span>
<span id="88"> 88</span>
<span id="89"> 89</span>
<span id="90"> 90</span>
<span id="91"> 91</span>
<span id="92"> 92</span>
<span id="93"> 93</span>
<span id="94"> 94</span>
<span id="95"> 95</span>
<span id="96"> 96</span>
<span id="97"> 97</span>
<span id="98"> 98</span>
<span id="99"> 99</span>
<span id="100">100</span>
<span id="101">101</span>
<span id="102">102</span>
<span id="103">103</span>
<span id="104">104</span>
<span id="105">105</span>
<span id="106">106</span>
<span id="107">107</span>
<span id="108">108</span>
<span id="109">109</span>
<span id="110">110</span>
<span id="111">111</span>
<span id="112">112</span>
<span id="113">113</span>
<span id="114">114</span>
<span id="115">115</span>
<span id="116">116</span>
<span id="117">117</span>
<span id="118">118</span>
<span id="119">119</span>
<span id="120">120</span>
<span id="121">121</span>
<span id="122">122</span>
<span id="123">123</span>
<span id="124">124</span>
<span id="125">125</span>
<span id="126">126</span>
<span id="127">127</span>
<span id="128">128</span>
<span id="129">129</span>
<span id="130">130</span>
<span id="131">131</span>
<span id="132">132</span>
<span id="133">133</span>
<span id="134">134</span>
<span id="135">135</span>
<span id="136">136</span>
<span id="137">137</span>
<span id="138">138</span>
<span id="139">139</span>
<span id="140">140</span>
<span id="141">141</span>
<span id="142">142</span>
<span id="143">143</span>
<span id="144">144</span>
<span id="145">145</span>
<span id="146">146</span>
<span id="147">147</span>
<span id="148">148</span>
<span id="149">149</span>
<span id="150">150</span>
<span id="151">151</span>
<span id="152">152</span>
<span id="153">153</span>
<span id="154">154</span>
<span id="155">155</span>
<span id="156">156</span>
<span id="157">157</span>
<span id="158">158</span>
<span id="159">159</span>
<span id="160">160</span>
<span id="161">161</span>
<span id="162">162</span>
<span id="163">163</span>
<span id="164">164</span>
<span id="165">165</span>
<span id="166">166</span>
<span id="167">167</span>
<span id="168">168</span>
<span id="169">169</span>
<span id="170">170</span>
<span id="171">171</span>
<span id="172">172</span>
<span id="173">173</span>
<span id="174">174</span>
<span id="175">175</span>
<span id="176">176</span>
<span id="177">177</span>
<span id="178">178</span>
<span id="179">179</span>
<span id="180">180</span>
<span id="181">181</span>
<span id="182">182</span>
<span id="183">183</span>
<span id="184">184</span>
<span id="185">185</span>
<span id="186">186</span>
<span id="187">187</span>
<span id="188">188</span>
<span id="189">189</span>
<span id="190">190</span>
<span id="191">191</span>
<span id="192">192</span>
<span id="193">193</span>
<span id="194">194</span>
<span id="195">195</span>
<span id="196">196</span>
<span id="197">197</span>
<span id="198">198</span>
<span id="199">199</span>
<span id="200">200</span>
<span id="201">201</span>
<span id="202">202</span>
<span id="203">203</span>
<span id="204">204</span>
<span id="205">205</span>
<span id="206">206</span>
<span id="207">207</span>
<span id="208">208</span>
<span id="209">209</span>
<span id="210">210</span>
<span id="211">211</span>
<span id="212">212</span>
<span id="213">213</span>
<span id="214">214</span>
<span id="215">215</span>
<span id="216">216</span>
<span id="217">217</span>
<span id="218">218</span>
<span id="219">219</span>
<span id="220">220</span>
<span id="221">221</span>
<span id="222">222</span>
<span id="223">223</span>
<span id="224">224</span>
<span id="225">225</span>
<span id="226">226</span>
<span id="227">227</span>
<span id="228">228</span>
<span id="229">229</span>
<span id="230">230</span>
<span id="231">231</span>
<span id="232">232</span>
<span id="233">233</span>
<span id="234">234</span>
<span id="235">235</span>
<span id="236">236</span>
<span id="237">237</span>
<span id="238">238</span>
<span id="239">239</span>
<span id="240">240</span>
<span id="241">241</span>
<span id="242">242</span>
<span id="243">243</span>
<span id="244">244</span>
<span id="245">245</span>
<span id="246">246</span>
<span id="247">247</span>
<span id="248">248</span>
<span id="249">249</span>
<span id="250">250</span>
<span id="251">251</span>
<span id="252">252</span>
<span id="253">253</span>
<span id="254">254</span>
<span id="255">255</span>
<span id="256">256</span>
<span id="257">257</span>
<span id="258">258</span>
<span id="259">259</span>
<span id="260">260</span>
<span id="261">261</span>
<span id="262">262</span>
<span id="263">263</span>
<span id="264">264</span>
<span id="265">265</span>
<span id="266">266</span>
<span id="267">267</span>
<span id="268">268</span>
<span id="269">269</span>
<span id="270">270</span>
<span id="271">271</span>
<span id="272">272</span>
<span id="273">273</span>
<span id="274">274</span>
<span id="275">275</span>
<span id="276">276</span>
<span id="277">277</span>
<span id="278">278</span>
<span id="279">279</span>
<span id="280">280</span>
<span id="281">281</span>
<span id="282">282</span>
<span id="283">283</span>
<span id="284">284</span>
<span id="285">285</span>
<span id="286">286</span>
<span id="287">287</span>
<span id="288">288</span>
<span id="289">289</span>
<span id="290">290</span>
<span id="291">291</span>
<span id="292">292</span>
<span id="293">293</span>
<span id="294">294</span>
<span id="295">295</span>
<span id="296">296</span>
<span id="297">297</span>
<span id="298">298</span>
<span id="299">299</span>
<span id="300">300</span>
<span id="301">301</span>
<span id="302">302</span>
<span id="303">303</span>
<span id="304">304</span>
<span id="305">305</span>
<span id="306">306</span>
<span id="307">307</span>
<span id="308">308</span>
<span id="309">309</span>
<span id="310">310</span>
<span id="311">311</span>
<span id="312">312</span>
<span id="313">313</span>
<span id="314">314</span>
<span id="315">315</span>
<span id="316">316</span>
<span id="317">317</span>
<span id="318">318</span>
<span id="319">319</span>
<span id="320">320</span>
<span id="321">321</span>
<span id="322">322</span>
<span id="323">323</span>
<span id="324">324</span>
<span id="325">325</span>
<span id="326">326</span>
<span id="327">327</span>
<span id="328">328</span>
<span id="329">329</span>
<span id="330">330</span>
<span id="331">331</span>
<span id="332">332</span>
<span id="333">333</span>
<span id="334">334</span>
<span id="335">335</span>
<span id="336">336</span>
<span id="337">337</span>
<span id="338">338</span>
<span id="339">339</span>
<span id="340">340</span>
<span id="341">341</span>
<span id="342">342</span>
<span id="343">343</span>
<span id="344">344</span>
<span id="345">345</span>
<span id="346">346</span>
<span id="347">347</span>
<span id="348">348</span>
<span id="349">349</span>
<span id="350">350</span>
<span id="351">351</span>
<span id="352">352</span>
<span id="353">353</span>
<span id="354">354</span>
<span id="355">355</span>
<span id="356">356</span>
<span id="357">357</span>
<span id="358">358</span>
<span id="359">359</span>
<span id="360">360</span>
<span id="361">361</span>
<span id="362">362</span>
<span id="363">363</span>
<span id="364">364</span>
<span id="365">365</span>
<span id="366">366</span>
<span id="367">367</span>
<span id="368">368</span>
<span id="369">369</span>
<span id="370">370</span>
<span id="371">371</span>
<span id="372">372</span>
<span id="373">373</span>
<span id="374">374</span>
<span id="375">375</span>
<span id="376">376</span>
<span id="377">377</span>
<span id="378">378</span>
<span id="379">379</span>
<span id="380">380</span>
<span id="381">381</span>
<span id="382">382</span>
<span id="383">383</span>
<span id="384">384</span>
<span id="385">385</span>
<span id="386">386</span>
<span id="387">387</span>
<span id="388">388</span>
<span id="389">389</span>
<span id="390">390</span>
<span id="391">391</span>
<span id="392">392</span>
<span id="393">393</span>
<span id="394">394</span>
<span id="395">395</span>
<span id="396">396</span>
<span id="397">397</span>
<span id="398">398</span>
<span id="399">399</span>
<span id="400">400</span>
<span id="401">401</span>
<span id="402">402</span>
<span id="403">403</span>
<span id="404">404</span>
<span id="405">405</span>
<span id="406">406</span>
<span id="407">407</span>
<span id="408">408</span>
<span id="409">409</span>
<span id="410">410</span>
<span id="411">411</span>
</pre><pre class="rust"><code><span class="kw">use</span> <span class="ident">std::collections</span>::{<span class="ident">BTreeMap</span>, <span class="ident">BTreeSet</span>};

<span class="kw">use</span> <span class="ident">anyhow::Result</span>;
<span class="kw">use</span> <span class="ident">serde</span>::{<span class="ident">Deserialize</span>, <span class="ident">Serialize</span>};

<span class="kw">use</span> <span class="ident">abstio::MapName</span>;
<span class="kw">use</span> <span class="ident">abstutil::Timer</span>;
<span class="kw">use</span> <span class="ident">map_model::osm::RoadRank</span>;
<span class="kw">use</span> <span class="ident">map_model</span>::{<span class="ident">Block</span>, <span class="ident">Map</span>, <span class="ident">Perimeter</span>, <span class="ident">RoadID</span>, <span class="ident">RoadSideID</span>};
<span class="kw">use</span> <span class="ident">widgetry::Color</span>;

<span class="kw">use</span> <span class="kw">crate</span>::{<span class="ident">colors</span>, <span class="ident">App</span>};

<span class="doccomment">/// An opaque ID, won&#39;t be contiguous as we adjust boundaries</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">PartialEq</span>, <span class="ident">Eq</span>, <span class="ident">PartialOrd</span>, <span class="ident">Ord</span>, <span class="ident">Hash</span>, <span class="ident">Serialize</span>, <span class="ident">Deserialize</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">NeighborhoodID</span>(<span class="ident">usize</span>);

<span class="doccomment">/// Identifies a single / unmerged block, which never changes</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">PartialEq</span>, <span class="ident">Eq</span>, <span class="ident">PartialOrd</span>, <span class="ident">Ord</span>, <span class="ident">Hash</span>, <span class="ident">Serialize</span>, <span class="ident">Deserialize</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">BlockID</span>(<span class="ident">usize</span>);

<span class="comment">// Some states want this</span>
<span class="kw">impl</span> <span class="ident">widgetry::mapspace::ObjectID</span> <span class="kw">for</span> <span class="ident">NeighborhoodID</span> {}
<span class="kw">impl</span> <span class="ident">widgetry::mapspace::ObjectID</span> <span class="kw">for</span> <span class="ident">BlockID</span> {}

<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Serialize</span>, <span class="ident">Deserialize</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Partitioning</span> {
    <span class="kw">pub</span> <span class="ident">map</span>: <span class="ident">MapName</span>,
    <span class="ident">neighborhoods</span>: <span class="ident">BTreeMap</span><span class="op">&lt;</span><span class="ident">NeighborhoodID</span>, (<span class="ident">Block</span>, <span class="ident">Color</span>)<span class="op">&gt;</span>,
    <span class="comment">// The single / unmerged blocks never change</span>
    <span class="ident">single_blocks</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">Block</span><span class="op">&gt;</span>,

    <span class="ident">neighborhood_id_counter</span>: <span class="ident">usize</span>,

    <span class="comment">// Invariant: This is a surjection, every block belongs to exactly one neighborhood</span>
    <span class="ident">block_to_neighborhood</span>: <span class="ident">BTreeMap</span><span class="op">&lt;</span><span class="ident">BlockID</span>, <span class="ident">NeighborhoodID</span><span class="op">&gt;</span>,

    <span class="ident">use_expensive_blockfinding</span>: <span class="ident">bool</span>,
}

<span class="kw">impl</span> <span class="ident">Partitioning</span> {
    <span class="doccomment">/// Only valid before the LTN tool has been activated this session</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">empty</span>() -&gt; <span class="ident">Partitioning</span> {
        <span class="ident">Partitioning</span> {
            <span class="ident">map</span>: <span class="ident">MapName::new</span>(<span class="string">&quot;zz&quot;</span>, <span class="string">&quot;temp&quot;</span>, <span class="string">&quot;orary&quot;</span>),
            <span class="ident">neighborhoods</span>: <span class="ident">BTreeMap::new</span>(),
            <span class="ident">single_blocks</span>: <span class="ident">Vec::new</span>(),

            <span class="ident">neighborhood_id_counter</span>: <span class="number">0</span>,

            <span class="ident">block_to_neighborhood</span>: <span class="ident">BTreeMap::new</span>(),

            <span class="ident">use_expensive_blockfinding</span>: <span class="bool-val">false</span>,
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="ident">bool</span> {
        <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">is_empty</span>()
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">seed_using_heuristics</span>(<span class="ident">app</span>: <span class="kw-2">&amp;</span><span class="ident">App</span>, <span class="ident">timer</span>: <span class="kw-2">&amp;mut</span> <span class="ident">Timer</span>) -&gt; <span class="ident">Partitioning</span> {
        <span class="comment">// Try the easy thing first, but then give up</span>
        <span class="lifetime">&#39;METHOD</span>: <span class="kw">for</span> <span class="ident">use_expensive_blockfinding</span> <span class="kw">in</span> [<span class="bool-val">false</span>, <span class="bool-val">true</span>] {
            <span class="kw">let</span> <span class="ident">map</span> <span class="op">=</span> <span class="kw-2">&amp;</span><span class="ident">app</span>.<span class="ident">map</span>;
            <span class="ident">timer</span>.<span class="ident">start</span>(<span class="string">&quot;find single blocks&quot;</span>);
            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">single_blocks</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">single_block_perims</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
            <span class="kw">for</span> <span class="kw-2">mut</span> <span class="ident">perim</span> <span class="kw">in</span> <span class="ident">Perimeter::find_all_single_blocks</span>(<span class="ident">map</span>) {
                <span class="comment">// TODO Some perimeters don&#39;t blockify after collapsing dead-ends. So do this</span>
                <span class="comment">// upfront, and separately work on any blocks that don&#39;t show up.</span>
                <span class="comment">// https://github.com/a-b-street/abstreet/issues/841</span>
                <span class="ident">perim</span>.<span class="ident">collapse_deadends</span>();
                <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Ok</span>(<span class="ident">block</span>) <span class="op">=</span> <span class="ident">perim</span>.<span class="ident">to_block</span>(<span class="ident">map</span>) {
                    <span class="ident">single_block_perims</span>.<span class="ident">push</span>(<span class="ident">block</span>.<span class="ident">perimeter</span>.<span class="ident">clone</span>());
                    <span class="ident">single_blocks</span>.<span class="ident">push</span>(<span class="ident">block</span>);
                }
            }
            <span class="ident">timer</span>.<span class="ident">stop</span>(<span class="string">&quot;find single blocks&quot;</span>);

            <span class="ident">timer</span>.<span class="ident">start</span>(<span class="string">&quot;partition&quot;</span>);
            <span class="kw">let</span> <span class="ident">partitions</span> <span class="op">=</span> <span class="ident">Perimeter::partition_by_predicate</span>(<span class="ident">single_block_perims</span>, <span class="op">|</span><span class="ident">r</span><span class="op">|</span> {
                <span class="comment">// &quot;Interior&quot; roads of a neighborhood aren&#39;t classified as arterial</span>
                <span class="ident">map</span>.<span class="ident">get_r</span>(<span class="ident">r</span>).<span class="ident">get_rank</span>() <span class="op">==</span> <span class="ident">RoadRank::Local</span>
            });

            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">merged</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
            <span class="kw">for</span> <span class="ident">perimeters</span> <span class="kw">in</span> <span class="ident">partitions</span> {
                <span class="comment">// If we got more than one result back, merging partially failed. Oh well?</span>
                <span class="kw">let</span> <span class="ident">stepwise_debug</span> <span class="op">=</span> <span class="bool-val">false</span>;
                <span class="ident">merged</span>.<span class="ident">extend</span>(<span class="ident">Perimeter::merge_all</span>(
                    <span class="ident">map</span>,
                    <span class="ident">perimeters</span>,
                    <span class="ident">stepwise_debug</span>,
                    <span class="ident">use_expensive_blockfinding</span>,
                ));
            }
            <span class="ident">timer</span>.<span class="ident">stop</span>(<span class="string">&quot;partition&quot;</span>);

            <span class="ident">timer</span>.<span class="ident">start_iter</span>(<span class="string">&quot;blockify&quot;</span>, <span class="ident">merged</span>.<span class="ident">len</span>());
            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">blocks</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
            <span class="kw">for</span> <span class="ident">perimeter</span> <span class="kw">in</span> <span class="ident">merged</span> {
                <span class="ident">timer</span>.<span class="ident">next</span>();
                <span class="kw">match</span> <span class="ident">perimeter</span>.<span class="ident">to_block</span>(<span class="ident">map</span>) {
                    <span class="prelude-val">Ok</span>(<span class="ident">block</span>) =&gt; {
                        <span class="ident">blocks</span>.<span class="ident">push</span>(<span class="ident">block</span>);
                    }
                    <span class="prelude-val">Err</span>(<span class="ident">err</span>) =&gt; {
                        <span class="macro">warn!</span>(<span class="string">&quot;Failed to make a block from a merged perimeter: {}&quot;</span>, <span class="ident">err</span>);
                    }
                }
            }

            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">neighborhoods</span> <span class="op">=</span> <span class="ident">BTreeMap::new</span>();
            <span class="kw">for</span> <span class="ident">block</span> <span class="kw">in</span> <span class="ident">blocks</span> {
                <span class="ident">neighborhoods</span>.<span class="ident">insert</span>(<span class="ident">NeighborhoodID</span>(<span class="ident">neighborhoods</span>.<span class="ident">len</span>()), (<span class="ident">block</span>, <span class="ident">Color::CLEAR</span>));
            }
            <span class="kw">let</span> <span class="ident">neighborhood_id_counter</span> <span class="op">=</span> <span class="ident">neighborhoods</span>.<span class="ident">len</span>();
            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">p</span> <span class="op">=</span> <span class="ident">Partitioning</span> {
                <span class="ident">map</span>: <span class="ident">map</span>.<span class="ident">get_name</span>().<span class="ident">clone</span>(),
                <span class="ident">neighborhoods</span>,
                <span class="ident">single_blocks</span>,

                <span class="ident">neighborhood_id_counter</span>,
                <span class="ident">block_to_neighborhood</span>: <span class="ident">BTreeMap::new</span>(),
                <span class="ident">use_expensive_blockfinding</span>,
            };

            <span class="comment">// TODO We could probably build this up as we go</span>
            <span class="kw">for</span> <span class="ident">id</span> <span class="kw">in</span> <span class="ident">p</span>.<span class="ident">all_block_ids</span>() {
                <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">neighborhood</span>) <span class="op">=</span> <span class="ident">p</span>.<span class="ident">neighborhood_containing</span>(<span class="ident">id</span>) {
                    <span class="ident">p</span>.<span class="ident">block_to_neighborhood</span>.<span class="ident">insert</span>(<span class="ident">id</span>, <span class="ident">neighborhood</span>);
                } <span class="kw">else</span> {
                    <span class="kw">if</span> <span class="op">!</span><span class="ident">use_expensive_blockfinding</span> {
                        <span class="comment">// Try the expensive check, then</span>
                        <span class="macro">error!</span>(
                            <span class="string">&quot;Block doesn&#39;t belong to any neighborhood? Retrying with expensive checks {:?}&quot;</span>,
                            <span class="ident">p</span>.<span class="ident">get_block</span>(<span class="ident">id</span>).<span class="ident">perimeter</span>
                        );
                        <span class="kw">continue</span> <span class="lifetime">&#39;METHOD</span>;
                    }
                    <span class="comment">// This will break everything downstream, so bail out immediately</span>
                    <span class="macro">panic!</span>(
                        <span class="string">&quot;Block doesn&#39;t belong to any neighborhood?! {:?}&quot;</span>,
                        <span class="ident">p</span>.<span class="ident">get_block</span>(<span class="ident">id</span>).<span class="ident">perimeter</span>
                    );
                }
            }

            <span class="ident">p</span>.<span class="ident">recalculate_coloring</span>();
            <span class="kw">return</span> <span class="ident">p</span>;
        }
        <span class="macro">unreachable!</span>()
    }

    <span class="doccomment">/// True if the coloring changed</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">recalculate_coloring</span>(<span class="kw-2">&amp;mut</span> <span class="self">self</span>) -&gt; <span class="ident">bool</span> {
        <span class="kw">let</span> <span class="ident">perims</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">Perimeter</span><span class="op">&gt;</span> <span class="op">=</span> <span class="self">self</span>
            .<span class="ident">neighborhoods</span>
            .<span class="ident">values</span>()
            .<span class="ident">map</span>(<span class="op">|</span><span class="ident">pair</span><span class="op">|</span> <span class="ident">pair</span>.<span class="number">0</span>.<span class="ident">perimeter</span>.<span class="ident">clone</span>())
            .<span class="ident">collect</span>();
        <span class="kw">let</span> <span class="ident">colors</span> <span class="op">=</span> <span class="ident">Perimeter::calculate_coloring</span>(<span class="kw-2">&amp;</span><span class="ident">perims</span>, <span class="ident">colors::NEIGHBORHOODS</span>.<span class="ident">len</span>())
            .<span class="ident">unwrap_or_else</span>(<span class="op">|</span><span class="op">|</span> (<span class="number">0</span>..<span class="ident">perims</span>.<span class="ident">len</span>()).<span class="ident">collect</span>());
        <span class="kw">let</span> <span class="ident">orig_coloring</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">Color</span><span class="op">&gt;</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">values</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">pair</span><span class="op">|</span> <span class="ident">pair</span>.<span class="number">1</span>).<span class="ident">collect</span>();
        <span class="kw">for</span> (<span class="ident">pair</span>, <span class="ident">color_idx</span>) <span class="kw">in</span> <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">values_mut</span>().<span class="ident">zip</span>(<span class="ident">colors</span>.<span class="ident">into_iter</span>()) {
            <span class="ident">pair</span>.<span class="number">1</span> <span class="op">=</span> <span class="ident">colors::NEIGHBORHOODS</span>[<span class="ident">color_idx</span> <span class="op">%</span> <span class="ident">colors::NEIGHBORHOODS</span>.<span class="ident">len</span>()];
        }
        <span class="kw">let</span> <span class="ident">new_coloring</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">Color</span><span class="op">&gt;</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">values</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">pair</span><span class="op">|</span> <span class="ident">pair</span>.<span class="number">1</span>).<span class="ident">collect</span>();
        <span class="ident">orig_coloring</span> <span class="op">!</span><span class="op">=</span> <span class="ident">new_coloring</span>
    }

    <span class="comment">// TODO Explain return value</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">transfer_block</span>(
        <span class="kw-2">&amp;mut</span> <span class="self">self</span>,
        <span class="ident">map</span>: <span class="kw-2">&amp;</span><span class="ident">Map</span>,
        <span class="ident">id</span>: <span class="ident">BlockID</span>,
        <span class="ident">old_owner</span>: <span class="ident">NeighborhoodID</span>,
        <span class="ident">new_owner</span>: <span class="ident">NeighborhoodID</span>,
    ) -&gt; <span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">NeighborhoodID</span><span class="op">&gt;</span><span class="op">&gt;</span> {
        <span class="macro">assert_ne!</span>(<span class="ident">old_owner</span>, <span class="ident">new_owner</span>);

        <span class="comment">// Is the newly expanded neighborhood a valid perimeter?</span>
        <span class="kw">let</span> <span class="ident">new_owner_blocks</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">BlockID</span><span class="op">&gt;</span> <span class="op">=</span> <span class="self">self</span>
            .<span class="ident">block_to_neighborhood</span>
            .<span class="ident">iter</span>()
            .<span class="ident">filter_map</span>(<span class="op">|</span>(<span class="ident">block</span>, <span class="ident">neighborhood</span>)<span class="op">|</span> {
                <span class="kw">if</span> <span class="kw-2">*</span><span class="ident">neighborhood</span> <span class="op">==</span> <span class="ident">new_owner</span> <span class="op">|</span><span class="op">|</span> <span class="kw-2">*</span><span class="ident">block</span> <span class="op">==</span> <span class="ident">id</span> {
                    <span class="prelude-val">Some</span>(<span class="kw-2">*</span><span class="ident">block</span>)
                } <span class="kw">else</span> {
                    <span class="prelude-val">None</span>
                }
            })
            .<span class="ident">collect</span>();
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">new_neighborhood_blocks</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">make_merged_blocks</span>(<span class="ident">map</span>, <span class="ident">new_owner_blocks</span>)<span class="question-mark">?</span>;
        <span class="kw">if</span> <span class="ident">new_neighborhood_blocks</span>.<span class="ident">len</span>() <span class="op">!</span><span class="op">=</span> <span class="number">1</span> {
            <span class="comment">// This happens when a hole would be created by adding this block. There are probably</span>
            <span class="comment">// some smaller blocks nearby to add first.</span>
            <span class="macro">bail!</span>(<span class="string">&quot;Couldn&#39;t add block -- you may need to add an intermediate block first to avoid a hole, or there&#39;s a bug you can&#39;t workaround yet&quot;</span>);
        }
        <span class="kw">let</span> <span class="ident">new_neighborhood_block</span> <span class="op">=</span> <span class="ident">new_neighborhood_blocks</span>.<span class="ident">pop</span>().<span class="ident">unwrap</span>();

        <span class="comment">// Is the old neighborhood, minus this block, still valid?</span>
        <span class="comment">// TODO refactor Neighborhood to BlockIDs?</span>
        <span class="kw">let</span> <span class="ident">old_owner_blocks</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">BlockID</span><span class="op">&gt;</span> <span class="op">=</span> <span class="self">self</span>
            .<span class="ident">block_to_neighborhood</span>
            .<span class="ident">iter</span>()
            .<span class="ident">filter_map</span>(<span class="op">|</span>(<span class="ident">block</span>, <span class="ident">neighborhood</span>)<span class="op">|</span> {
                <span class="kw">if</span> <span class="kw-2">*</span><span class="ident">neighborhood</span> <span class="op">==</span> <span class="ident">old_owner</span> <span class="op">&amp;&amp;</span> <span class="kw-2">*</span><span class="ident">block</span> <span class="op">!</span><span class="op">=</span> <span class="ident">id</span> {
                    <span class="prelude-val">Some</span>(<span class="kw-2">*</span><span class="ident">block</span>)
                } <span class="kw">else</span> {
                    <span class="prelude-val">None</span>
                }
            })
            .<span class="ident">collect</span>();
        <span class="kw">if</span> <span class="ident">old_owner_blocks</span>.<span class="ident">is_empty</span>() {
            <span class="comment">// We&#39;re deleting the old neighborhood!</span>
            <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">get_mut</span>(<span class="kw-2">&amp;</span><span class="ident">new_owner</span>).<span class="ident">unwrap</span>().<span class="number">0</span> <span class="op">=</span> <span class="ident">new_neighborhood_block</span>;
            <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">remove</span>(<span class="kw-2">&amp;</span><span class="ident">old_owner</span>).<span class="ident">unwrap</span>();
            <span class="self">self</span>.<span class="ident">block_to_neighborhood</span>.<span class="ident">insert</span>(<span class="ident">id</span>, <span class="ident">new_owner</span>);
            <span class="comment">// Tell the caller to recreate this SelectBoundary state, switching to the neighborhood</span>
            <span class="comment">// we just donated to, since the old is now gone</span>
            <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(<span class="ident">new_owner</span>));
        }

        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">old_neighborhood_blocks</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">make_merged_blocks</span>(<span class="ident">map</span>, <span class="ident">old_owner_blocks</span>.<span class="ident">clone</span>())<span class="question-mark">?</span>;
        <span class="comment">// We might be splitting the old neighborhood into multiple pieces! Pick the largest piece</span>
        <span class="comment">// as the old_owner (so the UI for trimming a neighborhood is less jarring), and create new</span>
        <span class="comment">// neighborhoods for the others.</span>
        <span class="ident">old_neighborhood_blocks</span>.<span class="ident">sort_by_key</span>(<span class="op">|</span><span class="ident">block</span><span class="op">|</span> <span class="ident">block</span>.<span class="ident">perimeter</span>.<span class="ident">interior</span>.<span class="ident">len</span>());
        <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">get_mut</span>(<span class="kw-2">&amp;</span><span class="ident">old_owner</span>).<span class="ident">unwrap</span>().<span class="number">0</span> <span class="op">=</span> <span class="ident">old_neighborhood_blocks</span>.<span class="ident">pop</span>().<span class="ident">unwrap</span>();
        <span class="kw">let</span> <span class="ident">new_splits</span> <span class="op">=</span> <span class="op">!</span><span class="ident">old_neighborhood_blocks</span>.<span class="ident">is_empty</span>();
        <span class="kw">for</span> <span class="ident">split_piece</span> <span class="kw">in</span> <span class="ident">old_neighborhood_blocks</span> {
            <span class="kw">let</span> <span class="ident">new_neighborhood</span> <span class="op">=</span> <span class="ident">NeighborhoodID</span>(<span class="self">self</span>.<span class="ident">neighborhood_id_counter</span>);
            <span class="self">self</span>.<span class="ident">neighborhood_id_counter</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
            <span class="comment">// Temporary color</span>
            <span class="self">self</span>.<span class="ident">neighborhoods</span>
                .<span class="ident">insert</span>(<span class="ident">new_neighborhood</span>, (<span class="ident">split_piece</span>, <span class="ident">Color::CLEAR</span>));
        }
        <span class="kw">if</span> <span class="ident">new_splits</span> {
            <span class="comment">// We need to update the owner of all single blocks in these new pieces</span>
            <span class="kw">for</span> <span class="ident">id</span> <span class="kw">in</span> <span class="ident">old_owner_blocks</span> {
                <span class="self">self</span>.<span class="ident">block_to_neighborhood</span>
                    .<span class="ident">insert</span>(<span class="ident">id</span>, <span class="self">self</span>.<span class="ident">neighborhood_containing</span>(<span class="ident">id</span>).<span class="ident">unwrap</span>());
            }
        }

        <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">get_mut</span>(<span class="kw-2">&amp;</span><span class="ident">new_owner</span>).<span class="ident">unwrap</span>().<span class="number">0</span> <span class="op">=</span> <span class="ident">new_neighborhood_block</span>;
        <span class="self">self</span>.<span class="ident">block_to_neighborhood</span>.<span class="ident">insert</span>(<span class="ident">id</span>, <span class="ident">new_owner</span>);
        <span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>)
    }

    <span class="doccomment">/// Needs to find an existing neighborhood to take the block, or make a new one</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">remove_block_from_neighborhood</span>(
        <span class="kw-2">&amp;mut</span> <span class="self">self</span>,
        <span class="ident">map</span>: <span class="kw-2">&amp;</span><span class="ident">Map</span>,
        <span class="ident">id</span>: <span class="ident">BlockID</span>,
        <span class="ident">old_owner</span>: <span class="ident">NeighborhoodID</span>,
    ) -&gt; <span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">NeighborhoodID</span><span class="op">&gt;</span><span class="op">&gt;</span> {
        <span class="comment">// Find all RoadSideIDs in the block matching the current neighborhood perimeter. Look for</span>
        <span class="comment">// the first one that borders another neighborhood, and transfer the block there.</span>
        <span class="comment">// TODO This can get unintuitive -- if we remove a block bordering two other</span>
        <span class="comment">// neighborhoods, which one should we donate to?</span>
        <span class="kw">let</span> <span class="ident">current_perim_set</span>: <span class="ident">BTreeSet</span><span class="op">&lt;</span><span class="ident">RoadSideID</span><span class="op">&gt;</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">neighborhoods</span>[<span class="kw-2">&amp;</span><span class="ident">old_owner</span>]
            .<span class="number">0</span>
            .<span class="ident">perimeter</span>
            .<span class="ident">roads</span>
            .<span class="ident">iter</span>()
            .<span class="ident">cloned</span>()
            .<span class="ident">collect</span>();
        <span class="kw">for</span> <span class="ident">road_side</span> <span class="kw">in</span> <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">get_block</span>(<span class="ident">id</span>).<span class="ident">perimeter</span>.<span class="ident">roads</span> {
            <span class="kw">if</span> <span class="op">!</span><span class="ident">current_perim_set</span>.<span class="ident">contains</span>(<span class="ident">road_side</span>) {
                <span class="kw">continue</span>;
            }
            <span class="comment">// Is there another neighborhood that has the other side of this road on its perimeter?</span>
            <span class="comment">// TODO We could map road -&gt; BlockID then use block_to_neighborhood</span>
            <span class="kw">let</span> <span class="ident">other_side</span> <span class="op">=</span> <span class="ident">road_side</span>.<span class="ident">other_side</span>();
            <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>((<span class="ident">new_owner</span>, <span class="kw">_</span>)) <span class="op">=</span> <span class="self">self</span>
                .<span class="ident">neighborhoods</span>
                .<span class="ident">iter</span>()
                .<span class="ident">find</span>(<span class="op">|</span>(<span class="kw">_</span>, (<span class="ident">block</span>, <span class="kw">_</span>))<span class="op">|</span> <span class="ident">block</span>.<span class="ident">perimeter</span>.<span class="ident">roads</span>.<span class="ident">contains</span>(<span class="kw-2">&amp;</span><span class="ident">other_side</span>))
            {
                <span class="kw">let</span> <span class="ident">new_owner</span> <span class="op">=</span> <span class="kw-2">*</span><span class="ident">new_owner</span>;
                <span class="kw">return</span> <span class="self">self</span>.<span class="ident">transfer_block</span>(<span class="ident">map</span>, <span class="ident">id</span>, <span class="ident">old_owner</span>, <span class="ident">new_owner</span>);
            }
        }

        <span class="comment">// We didn&#39;t find any match, so we&#39;re jettisoning a block near the edge of the map (or a</span>
        <span class="comment">// buggy area missing blocks). Create a new neighborhood with just this block.</span>
        <span class="kw">let</span> <span class="ident">new_owner</span> <span class="op">=</span> <span class="ident">NeighborhoodID</span>(<span class="self">self</span>.<span class="ident">neighborhood_id_counter</span>);
        <span class="self">self</span>.<span class="ident">neighborhood_id_counter</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
        <span class="comment">// Temporary color</span>
        <span class="self">self</span>.<span class="ident">neighborhoods</span>
            .<span class="ident">insert</span>(<span class="ident">new_owner</span>, (<span class="self">self</span>.<span class="ident">get_block</span>(<span class="ident">id</span>).<span class="ident">clone</span>(), <span class="ident">Color::CLEAR</span>));
        <span class="kw">let</span> <span class="ident">result</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">transfer_block</span>(<span class="ident">map</span>, <span class="ident">id</span>, <span class="ident">old_owner</span>, <span class="ident">new_owner</span>);
        <span class="kw">if</span> <span class="ident">result</span>.<span class="ident">is_err</span>() {
            <span class="comment">// Revert the change above!</span>
            <span class="self">self</span>.<span class="ident">neighborhoods</span>.<span class="ident">remove</span>(<span class="kw-2">&amp;</span><span class="ident">new_owner</span>).<span class="ident">unwrap</span>();
        }
        <span class="ident">result</span>
    }
}

<span class="comment">// Read-only</span>
<span class="kw">impl</span> <span class="ident">Partitioning</span> {
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">neighborhood_block</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">NeighborhoodID</span>) -&gt; <span class="kw-2">&amp;</span><span class="ident">Block</span> {
        <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">neighborhoods</span>[<span class="kw-2">&amp;</span><span class="ident">id</span>].<span class="number">0</span>
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">neighborhood_area_km2</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">NeighborhoodID</span>) -&gt; <span class="ident">String</span> {
        <span class="comment">// Convert from m^2 to km^2</span>
        <span class="kw">let</span> <span class="ident">area</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">neighborhood_block</span>(<span class="ident">id</span>).<span class="ident">polygon</span>.<span class="ident">area</span>() <span class="op">/</span> <span class="number">1_000_000.0</span>;
        <span class="macro">format!</span>(<span class="string">&quot;~{:.1} km²&quot;</span>, <span class="ident">area</span>)
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">neighborhood_color</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">NeighborhoodID</span>) -&gt; <span class="ident">Color</span> {
        <span class="self">self</span>.<span class="ident">neighborhoods</span>[<span class="kw-2">&amp;</span><span class="ident">id</span>].<span class="number">1</span>
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">all_neighborhoods</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw-2">&amp;</span><span class="ident">BTreeMap</span><span class="op">&lt;</span><span class="ident">NeighborhoodID</span>, (<span class="ident">Block</span>, <span class="ident">Color</span>)<span class="op">&gt;</span> {
        <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">neighborhoods</span>
    }

    <span class="comment">// Just used for initial creation</span>
    <span class="kw">fn</span> <span class="ident">neighborhood_containing</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">find_block</span>: <span class="ident">BlockID</span>) -&gt; <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">NeighborhoodID</span><span class="op">&gt;</span> {
        <span class="comment">// TODO We could probably build this mapping up when we do Perimeter::merge_all</span>
        <span class="kw">let</span> <span class="ident">find_block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">get_block</span>(<span class="ident">find_block</span>);
        <span class="kw">for</span> (<span class="ident">id</span>, (<span class="ident">block</span>, <span class="kw">_</span>)) <span class="kw">in</span> <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">neighborhoods</span> {
            <span class="kw">if</span> <span class="ident">block</span>.<span class="ident">perimeter</span>.<span class="ident">contains</span>(<span class="kw-2">&amp;</span><span class="ident">find_block</span>.<span class="ident">perimeter</span>) {
                <span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="kw-2">*</span><span class="ident">id</span>);
            }
        }
        <span class="prelude-val">None</span>
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">all_single_blocks</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="ident">Vec</span><span class="op">&lt;</span>(<span class="ident">BlockID</span>, <span class="kw-2">&amp;</span><span class="ident">Block</span>)<span class="op">&gt;</span> {
        <span class="self">self</span>.<span class="ident">single_blocks</span>
            .<span class="ident">iter</span>()
            .<span class="ident">enumerate</span>()
            .<span class="ident">map</span>(<span class="op">|</span>(<span class="ident">idx</span>, <span class="ident">block</span>)<span class="op">|</span> (<span class="ident">BlockID</span>(<span class="ident">idx</span>), <span class="ident">block</span>))
            .<span class="ident">collect</span>()
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">all_block_ids</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">BlockID</span><span class="op">&gt;</span> {
        (<span class="number">0</span>..<span class="self">self</span>.<span class="ident">single_blocks</span>.<span class="ident">len</span>()).<span class="ident">map</span>(<span class="ident">BlockID</span>).<span class="ident">collect</span>()
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_block</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">BlockID</span>) -&gt; <span class="kw-2">&amp;</span><span class="ident">Block</span> {
        <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">single_blocks</span>[<span class="ident">id</span>.<span class="number">0</span>]
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">block_to_neighborhood</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">BlockID</span>) -&gt; <span class="ident">NeighborhoodID</span> {
        <span class="self">self</span>.<span class="ident">block_to_neighborhood</span>[<span class="kw-2">&amp;</span><span class="ident">id</span>]
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">all_blocks_in_neighborhood</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">NeighborhoodID</span>) -&gt; <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">BlockID</span><span class="op">&gt;</span> {
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
        <span class="kw">for</span> (<span class="ident">block</span>, <span class="ident">n</span>) <span class="kw">in</span> <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">block_to_neighborhood</span> {
            <span class="kw">if</span> <span class="kw-2">*</span><span class="ident">n</span> <span class="op">==</span> <span class="ident">id</span> {
                <span class="ident">result</span>.<span class="ident">push</span>(<span class="kw-2">*</span><span class="ident">block</span>);
            }
        }
        <span class="ident">result</span>
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">some_block_in_neighborhood</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">NeighborhoodID</span>) -&gt; <span class="ident">BlockID</span> {
        <span class="kw">for</span> (<span class="ident">block</span>, <span class="ident">neighborhood</span>) <span class="kw">in</span> <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">block_to_neighborhood</span> {
            <span class="kw">if</span> <span class="ident">id</span> <span class="op">==</span> <span class="kw-2">*</span><span class="ident">neighborhood</span> {
                <span class="kw">return</span> <span class="kw-2">*</span><span class="ident">block</span>;
            }
        }
        <span class="macro">unreachable!</span>(<span class="string">&quot;{:?} has no blocks&quot;</span>, <span class="ident">id</span>);
    }

    <span class="doccomment">/// Blocks on the &quot;frontier&quot; are adjacent to the perimeter, either just inside or outside.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">calculate_frontier</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">perim</span>: <span class="kw-2">&amp;</span><span class="ident">Perimeter</span>) -&gt; <span class="ident">BTreeSet</span><span class="op">&lt;</span><span class="ident">BlockID</span><span class="op">&gt;</span> {
        <span class="kw">let</span> <span class="ident">perim_roads</span>: <span class="ident">BTreeSet</span><span class="op">&lt;</span><span class="ident">RoadID</span><span class="op">&gt;</span> <span class="op">=</span> <span class="ident">perim</span>.<span class="ident">roads</span>.<span class="ident">iter</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">id</span><span class="op">|</span> <span class="ident">id</span>.<span class="ident">road</span>).<span class="ident">collect</span>();

        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">frontier</span> <span class="op">=</span> <span class="ident">BTreeSet::new</span>();
        <span class="kw">for</span> (<span class="ident">block_id</span>, <span class="ident">block</span>) <span class="kw">in</span> <span class="self">self</span>.<span class="ident">all_single_blocks</span>() {
            <span class="kw">for</span> <span class="ident">road_side_id</span> <span class="kw">in</span> <span class="kw-2">&amp;</span><span class="ident">block</span>.<span class="ident">perimeter</span>.<span class="ident">roads</span> {
                <span class="comment">// If the perimeter has this RoadSideID on the same side, we&#39;re just inside. If it has</span>
                <span class="comment">// the other side, just on the outside. Either way, on the frontier.</span>
                <span class="kw">if</span> <span class="ident">perim_roads</span>.<span class="ident">contains</span>(<span class="kw-2">&amp;</span><span class="ident">road_side_id</span>.<span class="ident">road</span>) {
                    <span class="ident">frontier</span>.<span class="ident">insert</span>(<span class="ident">block_id</span>);
                    <span class="kw">break</span>;
                }
            }
        }
        <span class="ident">frontier</span>
    }

    <span class="comment">// Possibly returns multiple merged blocks. The input is never &quot;lost&quot; -- if any perimeter fails</span>
    <span class="comment">// to become a block, fail the whole operation.</span>
    <span class="kw">fn</span> <span class="ident">make_merged_blocks</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">map</span>: <span class="kw-2">&amp;</span><span class="ident">Map</span>, <span class="ident">input</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">BlockID</span><span class="op">&gt;</span>) -&gt; <span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">Block</span><span class="op">&gt;</span><span class="op">&gt;</span> {
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">perimeters</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
        <span class="kw">for</span> <span class="ident">id</span> <span class="kw">in</span> <span class="ident">input</span> {
            <span class="ident">perimeters</span>.<span class="ident">push</span>(<span class="self">self</span>.<span class="ident">get_block</span>(<span class="ident">id</span>).<span class="ident">perimeter</span>.<span class="ident">clone</span>());
        }
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">blocks</span> <span class="op">=</span> <span class="ident">Vec::new</span>();
        <span class="kw">let</span> <span class="ident">stepwise_debug</span> <span class="op">=</span> <span class="bool-val">false</span>;
        <span class="kw">for</span> <span class="ident">perim</span> <span class="kw">in</span> <span class="ident">Perimeter::merge_all</span>(
            <span class="ident">map</span>,
            <span class="ident">perimeters</span>,
            <span class="ident">stepwise_debug</span>,
            <span class="self">self</span>.<span class="ident">use_expensive_blockfinding</span>,
        ) {
            <span class="ident">blocks</span>.<span class="ident">push</span>(<span class="ident">perim</span>.<span class="ident">to_block</span>(<span class="ident">map</span>)<span class="question-mark">?</span>);
        }
        <span class="prelude-val">Ok</span>(<span class="ident">blocks</span>)
    }
}
</code></pre></div>
</section><section id="search" class="content hidden"></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="ltn" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.60.0 (7737e0b5c 2022-04-04)" ></div>
</body></html>