LeetCode: Search in Rotated Sorted Array

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) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int start = 0, end = n-1;
        while (start <= end) {
            int mid = (start+end)/2;
            if (target == A[mid]) return mid;
            else if (target < A[mid]) {
                if (A[start] < A[end] || A[mid] < A[end] || A[start] <= target) {
                    end = mid-1;
                } else {
                    start = mid+1;   
                }
            } else {
                if (A[start] < A[end] || A[mid] > A[start] || A[end] >= target) {
                    start = mid+1;
                } else {
                    end = mid-1;   
                }
            }
        }
        return -1;
    }
};