C++(씨쁠쁠)(cplusplus)-백준(baekjoon)(BaekJoon)코딩 1766번:문제집 답

#include <iostream>
#include <vector>
#include <functional>
#include <queue>
using namespace std;
int N, M,u,v,ind[32001];
vector <int> a[32001];
priority_queue <int,vector <int>,greater<int>> q;
int main() {
    cin >> N >> M;
    for (int i = 1; i <= M; i++)
    {
        cin >> u >> v;
        a[u].push_back(v);
        ind[v]++;
    }
    for (int i = 1; i <= N; i++)
    {
        if (ind[i] == 0)
            q.push(i);
    }
    for (int j = 1; j <= N; j++)
    {
        int x = q.top();
        q.pop();
        cout << x << ' ';
        for (int i = 0; i < a[x].size(); i++)
        {
            int y = a[x][i];
            ind[y]--;
            if (ind[y] == 0) { q.push(y); }
        }
    }
}