Search in Rotated Sorted Array

Suppose an array sorted in ascending order 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.

Your algorithm's runtime complexity must be in the order of O(log n).

Example 1:

Input: nums = [4,5,6,7,0,1,2], target = 0
Output: 4

Example 2:

Input: nums = [4,5,6,7,0,1,2], target = 3
Output: -1

class Solution {
public:
    int search(vector<int>& nums, int target) {
        if(nums.size()==0)
            return -1;
        return Search(nums, 0, nums.size()-1, target);
    }
    
    int Search(vector<int>& nums, int start, int end, int target)
    {
        if(start>end)
            return -1;
        int mid = start + (end-start)/2;
        if(nums[mid] == target)
        {
            return mid;
        }
        else if(nums[start]<=nums[mid])
        {
            if(target>=nums[start]&&target<nums[mid])
            {
                return Search(nums, start, mid-1, target);  
            }
            else
            {
                return Search(nums, mid+1, end, target);  
            }
            
        }else
        {
            if(target>nums[mid]&&target<=nums[end])
            {
                return Search(nums, mid+1, end, target);  
            }
            else
            {
                return Search(nums, start, mid-1, target);  
            }
        }
    }
};