From 0802268ed7ee0a54488515208b60382c73db7237 Mon Sep 17 00:00:00 2001
From: ericdouglas <eric.douglas.mail@gmail.com>
Date: Wed, 3 Jun 2015 12:04:42 -0300
Subject: [PATCH] Find closest number to be a square root of another number -
 bisection method

---
 .../src/03-lecture.js                         | 51 +++++++++++++++----
 1 file changed, 40 insertions(+), 11 deletions(-)

diff --git a/computer-science/01-introduction-to-cs-and-programming-mit/src/03-lecture.js b/computer-science/01-introduction-to-cs-and-programming-mit/src/03-lecture.js
index b0b4d83..2783dd5 100644
--- a/computer-science/01-introduction-to-cs-and-programming-mit/src/03-lecture.js
+++ b/computer-science/01-introduction-to-cs-and-programming-mit/src/03-lecture.js
@@ -69,23 +69,52 @@ var prompt = require( 'prompt' );
 
 // });
 
-// Find closest number to be a square root of another number
-var x          = 25;
+// // Find closest number to be a square root of another number - Brute Force
+// var x          = 25;
+// var epsilon    = 0.01;
+// var numGuesses = 0;
+// var ans        = 0;
+
+// while ( Math.abs( Math.pow( ans, 2 ) - x ) >= epsilon && ans <= x ) {
+
+//   ans += 0.00001;
+//   numGuesses += 1;
+
+// }
+
+// console.log( 'numGuesses: ' + numGuesses );
+
+// if ( Math.abs( Math.pow( ans, 2 ) - x >= epsilon )) {
+//   console.log( 'Failed on square root of ' + x.toString());
+// } else {
+//   console.log( ans.toString() + ' is close to square root of ' + x.toString());
+// }
+
+// Find closest number to be a square root of another number - bisection method
+var x          = 12345;
 var epsilon    = 0.01;
 var numGuesses = 0;
-var ans        = 0;
+var low        = 0;
+var high       = x;
+var ans        = ( high + low ) / 2;
 
 while ( Math.abs( Math.pow( ans, 2 ) - x ) >= epsilon && ans <= x ) {
 
-  ans += 0.00001;
   numGuesses += 1;
 
+  if ( Math.pow( ans, 2 ) < x ) {
+
+    low = ans;
+
+  } else {
+
+    high = ans;
+
+  }
+
+  ans = ( high + low ) / 2;
+
 }
 
-console.log( 'numGuesses: ' + numGuesses );
-
-if ( Math.abs( Math.pow( ans, 2 ) - x >= epsilon )) {
-  console.log( 'Failed on square root of ' + x.toString());
-} else {
-  console.log( ans.toString() + ' is close to square root of ' + x.toString());
-}
\ No newline at end of file
+console.log( 'numGuesses:', numGuesses );
+console.log( ans, 'is close to square root of', x );
\ No newline at end of file