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.

面试考过这道题，注意边界条件，先把旋转位置找出来，再一步一步找key。

class Solution {
public:
    int search(int A[], int n, int target) {
        int left = 0 ; 
        int right = n-1 ;
        
        while(left <= right)
        {
            int mid = (left + right)/2;
            if(A[mid] == target)return mid;
            
            if(A[left] <= A[mid])
            {
                if(target < A[mid] && target >= A[left])
                right =  mid -1;
                else
                left = mid + 1;
            }
            else
            {
                if(target >A[mid] &&target <=A[right])
                left = mid +1;
                else
                right = mid -1;
            }
        }
        return -1;
    }
};