Search in Rotated Sorted Array

Question:

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.

Solution:

 1 class Solution {
 2 public:
 3     int search(vector<int>& nums, int target) {
 4                 int left=0;
 5     int right=nums.size()-1;
 6     if(left==right && nums[left]==target)
 7         return left;
 8     while(left!=right)
 9     {
10         int mid=(left+right)/2;
11         if(nums[mid]==target) return mid;
12         if(nums[left]<=nums[mid])
13         {
14             if(nums[left]<=target && target<=nums[mid])
15                 right=mid;
16             else
17                 left=mid+1;
18         }
19         else
20         {
21             if(nums[mid]<=target && target<=nums[right])
22                 left=mid+1;
23             else
24                 right=mid;
25         }
26         if(left==right && nums[left]==target)
27             return left;
28     }
29     return -1;
30         
31     }
32 };