백준 15664번 N과 M(10) C++

https://www.acmicpc.net/problem/15664

15664번: N과 M (10)

 

백트래킹을 하는데, 비내림차순으로 하고, 중복을 제거해야한다.

 

#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, m;
vector<int> v;
vector<int> idxes;
vector<bool> visited;
set<vector<int>> st;

void BT(int cnt) {
    if (cnt >= m) {
        vector<int> tmp;
        for (auto a : idxes) {
            tmp.push_back(v[a]);
        }
        st.insert(tmp);
        return;
    }
    for (int i = 0; i < n; i++) {
        if (visited[i]) continue;
        if (idxes.size() > 0) {
            if (v[idxes.back()] > v[i]) continue;
        }
        visited[i] = true;
        idxes.push_back(i);
        BT(cnt + 1);
        visited[i] = false;
        idxes.pop_back();
    }
}

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

    cin >> n >> m;
    v = vector<int>(n);
    visited = vector<bool>(n, false);
    for (int i = 0; i < n; i++) cin >> v[i];
    sort(v.begin(), v.end());
    BT(0);
    for (auto a : st) {
        for (auto b : a) {
            cout << b << " ";
        }
        cout << "\n";
    }
}