题解 | #查找数组元素位置#

{"css":"","js":"function indexOf(arr, item) {\n    var head = 0,\n        tail = arr.length - 1,\n        mid = Math.floor((head + tail) / 2);\n    \n    while(head <= tail){\n        if(arr[mid] == item){\n            return mid;\n        }\n        else if(arr[mid] > item){\n            tail = mid - 1;\n            mid = Math.floor((head + tail) / 2);\n        }\n        else{\n            head = mid + 1;\n            mid = Math.floor((head + tail) / 2);\n        }\n\n    }\n    \n    return -1;\n}","html":"","libs":[]}

好久没刷题了，二分查找自己刚开始细节一直没处理好，尤其是判定退出循环那里