[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.

class Solution {
public:
    int search(int A[], int n, int target) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        //find pivot
        int endval=A[n-1];
        int i;
        for(i=n-1;i>=0;i--)
        {
            if(A[i] > endval) break;
        }
        int pivot=i+1;
        
        //do binary search
        int start=pivot;
        int end=pivot-1+n;
        do{
            int median=(start+end)/2;
            if(A[median%n] == target) return median%n;
            if(A[median%n] > target) end--;
            else
                start++;
                
        }while(start<=end);
        
        return -1;
    }
};