Cod sursa(job #2207505)

Utilizator TooHappyMarchitan Teodor TooHappy Data 25 mai 2018 20:11:57
Problema Sortare topologica Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.31 kb
#include <bits/stdc++.h>
using namespace std;
     
ifstream in("sortaret.in");
ofstream out("sortaret.out");

vector< vector< int > > G;
vector< bool > viz;
vector< int > grad;
stack< int > s;

void DFS(int nod) {
    viz[nod] = true;

    // cout << nod << " ";

    s.push(nod);

    for(auto vecin: G[nod]) {
        if(!viz[vecin]) {
            DFS(vecin);
        }
    }
    // cout << nod << " ";
}

int main() {
    ios::sync_with_stdio(false); in.tie(0); out.tie(0);

    int n, m; in >> n >> m;
    
    G.resize(n + 1); viz.resize(n + 1, false); grad.resize(n + 1, 0);
    for(int i = 1; i <= m; ++i) {
        int x, y; in >> x >> y;
        G[x].push_back(y);
        grad[y]++;
    }

    // for(int i = 1; i <= n; ++i) {
    //     cout << grad[i] << " ";
    // }
    // cout << endl;

    // for(int i = 1; i <= n; ++i) {
    //     cout << i << " -> ";
    //     for(auto vecin: G[i]) {
    //         cout << vecin << " ";
    //     }
    //     cout << "\n";
    // }

    for(int i = 1; i <= n; ++i) {
        if(grad[i] == 0) {
            DFS(i);
            break;
        }
    }

    vector< int > ans;
    while(!s.empty()) {
        ans.push_back(s.top());
        s.pop();
    }

    for(int i = n - 1; i >= 0; --i) {
        out << ans[i] << " ";
    }

    in.close(); out.close();
     
    return 0;
}