题解 | 二分查找-I

class Solution {
public:
    int search_helper(vector<int>& nums, int target, int left, int right)
    {
        if (nums.empty()) return -1;
        if (left > right) return -1;

        int medium = left + (right - left) / 2;
        
        if (nums[medium] > target) {
            return search_helper(nums, target, left, medium - 1);
        } else if (nums[medium] < target) {
            return search_helper(nums, target, medium + 1, right);
        } else {
            return medium;
        }
    }
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型vector 
     * @param target int整型 
     * @return int整型
     */
    int search(vector<int>& nums, int target) {
        // write code here
        int left = 0;
        int right = nums.size() - 1;
        int medium = (left + right)/2;
        return search_helper(nums, target, left, right);
    }
};