Second take: Binary search algorithm

jtj · Aug 30, 2009 · 844c331 · 844c331
1 parent fdd3c10
commit 844c331
Showing 1 changed file with 4 additions and 5 deletions.
diff --git a/algorithms/searching/binary-search/binary-search.js b/algorithms/searching/binary-search/binary-search.js
@@ -31,8 +31,8 @@
 function binarySearch(items, value){
 
     var startIndex  = 0,
-        middle      = Math.floor(items.length / 2),
-        stopIndex   = items.length;
+        stopIndex   = items.length - 1,
+        middle      = Math.floor((stopIndex + startIndex)/2);
 
     while(items[middle] != value && startIndex < stopIndex){
 
@@ -44,10 +44,9 @@ function binarySearch(items, value){
         }
 
         //recalculate middle
-        middle = Math.floor((stopIndex + startIndex)/2);
-
+        middle = Math.floor((stopIndex + startIndex)/2);    
     }
 
     //make sure it's the right value
     return (items[middle] != value) ? -1 : middle;
-}
+}