Cod sursa(job #2952681)

Utilizator Chiri_Robert Chiributa Chiri_ Data 9 decembrie 2022 18:36:54
Problema Sortare topologica Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.42 kb
#include <bits/stdc++.h>

using namespace std;

ifstream fin("sortaret.in");
ofstream fout("sortaret.out");

int n, m, x, y;
vector<int> a[50001];
int grad[50001];
bool viz[50001];

void sorttop1() {
    queue<int> q;
    for (int i = 1; i <= n; i++) {
        if (!grad[i]) {
            q.push(i);
            viz[i] = 1;
        }
    }
    while (!q.empty()) {
        int t = q.front();
        fout << t << " ";
        for (int x : a[t]) {
            if (!viz[x]) {
                grad[x]--;

                if (!grad[x]) {
                    viz[x] = 1;
                    q.push(x);
                }
            }
        }
        q.pop();
    }
}

void dfs(int st, stack<int>& s) {
    for (int x : a[st]) {
        if (!viz[x]) {
            viz[x] = 1;
            dfs(x, s);
        }
    }
    s.push(st);
}

void sorttop2() {
    stack<int> rez;

    for (int i = 1; i <= n; i++) {
        if (!viz[i]) {
            viz[i] = 1;
            dfs(i, rez);
        }
    }

    while (!rez.empty()) {
        fout << rez.top() << " ";
        rez.pop();
    }
}

int main() {
    fin >> n >> m;
    for (int i = 0; i < m; i++) {
        fin >> x >> y;
        a[x].push_back(y);
    }

    for (int i = 1; i <= n; i++) {
        sort(a[i].begin(), a[i].end());
        a[i].erase(unique(a[i].begin(), a[i].end()), a[i].end());
        for (int x : a[i]) {
            grad[x]++;
        }
    }

    sorttop1();
    sorttop2();
}