题目：

Suppose a sorted array 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.

题解：

这道题是一道常见的二分查找法的变体题。

要解决这道题，需要明确rotated sorted array的特性，那么就是至少有一侧是排好序的（无论pivot在哪，自己画看看）。接下来就只需要按照这个特性继续写下去就好。以下就以伪代码方法来说明：

  1. high = mid - 1;
                }                                                                            low = mid + 1;
                }                      }
            
             }