33. Search in Rotated Sorted Array

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.

(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).

You are given a target value to search. If found in the array return its index, otherwise return -1.

You may assume no duplicate exists in the array.

1 /** 2  * @param {number[]} nums 3  * @param {number} target 4  * @return {number} 5  */ 6 var search = function(A, target) { 7     //有序数组查找固定值，第一反应就是二分。  8     var lo = 0; 9     var hi = A.length - 1;10     11     while (lo < hi) {12         var mid = Math.floor((lo + hi) / 2);13         if (A[mid] == target) return mid;14         15         if (A[lo] <= A[mid]) {16             if (target >= A[lo] && target < A[mid]) {17                 hi = mid - 1;18             } else {19                 lo = mid + 1;20             }21         } else {22             if (target > A[mid] && target <= A[hi]) {23                 lo = mid + 1;24             } else {25                 hi = mid - 1;26             }27         }28     }29     return A[lo] == target ? lo : -1;30 };