{"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