백준 2623번 음악프로그램 C++

https://www.acmicpc.net/problem/2623

2623번: 음악프로그램

 

위상 정렬

 

#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;

vector<int> inDegree;
vector<vector<int>> graph;

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

    int n, m;
    cin >> n >> m;

    inDegree = vector<int>(n + 1, 0);
    graph = vector<vector<int>>(n + 1, vector<int>());

    for (int i = 0; i < m; i++) {
        int cnt;
        cin >> cnt;
        int lastSinger = 0;
        for (int j = 0; j < cnt; j++) {
            int singer;
            cin >> singer;
            if (lastSinger != 0) {
                graph[lastSinger].push_back(singer);
                inDegree[singer]++;
            }
            lastSinger = singer;
        }
    }
    queue<int> q;
    for (int i = 1; i <= n; i++) {
        if (inDegree[i] == 0) q.push(i);
    }

    vector<int> ans;

    while (!q.empty()) {
        int curr = q.front();
        ans.push_back(curr);
        q.pop();

        for (auto next : graph[curr]) {
            if (--inDegree[next] == 0) q.push(next);
        }
    }

    if (ans.size() == n) {
        for (auto a : ans) cout << a << " ";
    }
    else cout << 0;
}