只有10%程序员能正确实现二分查找算法
//Copyright 2009 Nicholas C. Zakas. All rights reserved.
//MIT-Licensed, see source file
function binarySearch(items, value){
var startIndex = 0,
stopIndex = items.length - 1,
middle = Math.floor((stopIndex + startIndex)/2);
while(items[middle] != value && startIndex < stopIndex){
//adjust search area(调整查找范围)
if (value < items[middle]){
stopIndex = middle - 1;
} else if (value > items[middle]){
startIndex = middle + 1;
}
//recalculate middle(重新计算中项索引)
middle = Math.floor((stopIndex + startIndex)/2);
}
//make sure it's the right value(确保返回正确的值)
return (items[middle] != value) ? -1 : middle;
}