[LeetCode]Search in Rotated Sorted Array

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.

思考：二分搜索。

class Solution {
public:
    int search(int A[], int n, int target) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int left=0;
        int right=n-1;
        int mid;

		while(left<=right)
		{
			mid=(left+right)>>1;
			if(A[mid]==target) return mid;
			else if(A[mid]>=A[left])
			{
				if(A[left]<=target&&target<=A[mid]) right=mid-1;
				else left=mid+1;
			}
			else 
			{
				if(A[mid]<=target&&target<=A[right]) left=mid+1;
				else right=mid-1;
			}
		}

        return -1;
    }
};