Cod sursa(job #2907529)

Utilizator andreicontorandrei contor andreicontor Data 30 mai 2022 17:01:46
Problema Sortare topologica Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.02 kb
#include <fstream>
#include <cstring>
#include <vector>
using namespace std;

ifstream f("sortaret.in");
ofstream g("sortaret.out");

#define MAXN 50100
#define pb push_back

int N, M, deg[MAXN], Q[MAXN]; vector<int> G[MAXN];

// deg[x] = gradul exterior al nodului x
// folosesc o coada Q in care introduc pe rand nodurile care
// au gradul exterior zero
// complexitate O(N+M)

void solve(void)
{
    int i, x;
    vector<int>::iterator it;

    for(x = 1; x <= N; x++)
        if(deg[x] == 0)
            Q[++Q[0]] = x;

    for(i = 1; i <= N; i++)
    {
        x = Q[i];
        for(it = G[x].begin(); it != G[x].end(); ++it)
        {
            deg[*it]--;
            if(deg[*it] == 0)
                Q[++Q[0]] = *it;
        }
    }
}

void read_data(void)
{
    int i, a, b;

    f>>N>>M;
    for(i = 1; i <= M; i++)
        f>>a>>b, G[a].pb(b), deg[b]++;
}

void write_data(void)
{
    int i;

    for(i = 1; i <= N; i++)
        g<<Q[i]<<" ";
}

int main(void)
{


    read_data();
    solve();
    write_data();

    return 0;
}