연산자 끼워넣기 (재귀)

https://www.acmicpc.net/problem/15658

15658번: 연산자 끼워넣기 (2)

pair<int, int> calc(vector<int>& num, int index, int cur, int plus, int minus, int mul, int div)

#include <iostream>
#include <vector>
#include <algorithm>
 
using namespace std;
 
pair<int, int> calc(vector<int>& num, int index, int cur, int plus, int minus, int mul, int div)
{
    int n = num.size();
    if (index == n)
    {
        return make_pair(cur, cur);
    }
    vector<pair<int, int>> res;
 
    if(plus > 0)
        res.push_back(calc(num, index + 1, cur + num[index], plus - 1, minus, mul, div));
    if(minus > 0)
        res.push_back(calc(num, index + 1, cur - num[index], plus, minus - 1, mul, div));
    if(mul > 0)
        res.push_back(calc(num, index + 1, cur * num[index], plus, minus, mul - 1, div));
    if (div > 0)
        res.push_back(calc(num, index + 1, cur / num[index], plus, minus, mul, div - 1));
 
    auto ans = res[0];
    for (auto p : res)
    {
        //최대값
        if (ans.first < p.first)
            ans.first = p.first;
        //최소값
        if (ans.second > p.second)
            ans.second = p.second;
    }
    
    //pair를 return
    return ans;  
}
 
int main()
{
    int n;
    cin >> n;
    
    int plus, minus, mul, div;
 
    vector<int> num(n);
 
    for (int i = 0; i < n; i++)
        cin >> num[i];
 
    cin >> plus >> minus >> mul >> div;
 
    auto p = calc(num, 1, num[0], plus, minus, mul, div);
    cout << p.first << '\n';
    cout << p.second << '\n';
 
 
    return 0;
}