LeetCode Problem : Search in Rotated Sorted Array

Problem

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.

Code

int rs_r(int A[], int l,int r, int target){
    if(l == r)
    {
        if(A[l - 1] == target)
            return l - 1;
        return -1;
    }
    int mid = (l + r)/2;
    if(A[mid - 1] >= A[l - 1]){
        if(target == A[mid - 1]){
            return mid - 1;
        }
        else if(target < A[mid - 1] && target >= A[l - 1])
            rs_r(A,l,mid - 1,target);
        else
            rs_r(A,mid + 1,r,target);
    }
    else{
        if(target == A[mid - 1]){
            return mid - 1;
        }
        else if(target > A[mid - 1] && target <= A[r - 1])
            rs_r(A,mid + 1,r,target);
        else
            rs_r(A,l,mid - 1,target);
    }
}
int search(int A[], int n, int target) {
    // Note: The Solution object is instantiated only once and is reused by each test case.
    int l = 1,r = n;
    return rs_r(A,l,r,target);
}