leetcode_33.cpp

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