js的二分法求陣列中某個值的索引
阿新 • • 發佈:2018-12-01
為了解決最後一個數字無法顯示正確索引的問題,我直接加了一個判斷最後一個索引的判斷
<!DOCTYPE html>
<html>
<head>
<title>123</title>
<meta charset="utf-8">
</head>
<body>
<script type="text/javascript">
var arr = [1,2,3,4,5,6,7,8,9];
// var target = 4;
function two(arr,target, left,right){
var mid = Math.floor((left + right)/2);
if (arr[arr.length - 1] == target) {
document.write("索引是" + (arr.length-1));
}
else{
if (arr[mid] > target) {
two(arr,target,left,mid);
}
else if (arr[mid] < target) {
two(arr,target,mid,right);
}
else {
document.write("索引是" + mid);
}
}
}
two(arr,6,0,arr.length-1);
</script>
</body>
</html>