백준18429번 근손실 C++

https://www.acmicpc.net/problem/18429

18429번: 근손실

 

백트래킹

 

#include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <algorithm>
#include <utility>
#include <stack>
#include <queue>
#include <math.h>
#include <set>
#include <map>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <limits.h>

using namespace std;
using int64 = long long;

int n, k;
int ans = 0;
vector<int> v;
vector<int> idxes;
vector<bool> visited;

void BT(int curr, int cnt) {
    if (cnt >= n) {
        int currVal = 500;
        bool possible = true;
        for (int i = 0; i < n; i++) {
            currVal -= k;
            currVal += v[idxes[i]];
            if (currVal < 500) {
                possible = false;
                break;
            }
        }
        if (possible) ans++;
        return;
    }
    for (int i = 0; i < n; i++) {
        if (visited[i]) continue;
        visited[i] = true;
        idxes.push_back(i);
        BT(i + 1, cnt + 1);
        visited[i] = false;
        idxes.pop_back();
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> n >> k;
    v = vector<int>(n);
    visited = vector<bool>(n, false);
    for (int i = 0; i < n; i++) {
        cin >> v[i];
    }
    BT(0, 0);
    cout << ans;
}