[LeetCode] 33. 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.

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