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.

 

public class Solution {
    public int search(int[] nums, int target) {
        int start = 0;
        int end = nums.length-1;
        return search(nums, target, start, end);
    }

	private int search(int[] nums, int target, int start, int end) {
		if (start>end) {
			return -1;
		}
		int mid = (start+end)/2;
		if (target == nums[mid]) {
			return mid;
		}
		if (nums[mid] > nums[end]) {
			if (target<nums[mid] && target>=nums[start]) {
				return search(nums, target, start, mid-1);
			} else {
				return search(nums, target, mid+1, end);
			}
		} else {
			if (target>nums[mid] && target<=nums[end]) {
				return search(nums, target, mid+1, end);
			} else {
				return search(nums, target, start, mid-1);
			}
		}
	}
}