递归版 二分查找

#include<iostream>
#include<vector>

using namespace std;

int Find(vector<int> &nums, int target, int left, int right)
{
    if(left <= right)
    {
        int mid = (left + right) / 2;
        if(nums[mid] == target) return mid;
        if(nums[mid] < target) return Find(nums, target, mid + 1, right);
        if(nums[mid] > target) return Find(nums, target, left, mid - 1);
    }
    
    return -2;
}

int TwoFind(vector<int> &nums, int target)
{
    return Find(nums, target, 0, nums.size() - 1);
}

int main()
{
    int n;
    cin >> n;
    vector<int> nums(n);
    
    for(int i = 0; i < n; i++)
    {
        cin >> nums[i];
    }

    int target;
    cin >> target;

    cout << TwoFind(nums, target) + 1;
}