Cod sursa(job #2979985)

Utilizator MihiBluBalau Mihai MihiBlu Data 16 februarie 2023 09:43:51
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.59 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

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

bool a[50010], gasit;
int n, m, dist[50010];
vector <pair <int, int>> v[50010];
queue <int> q;

void p(int nod, int c)
{
    a[nod]=1;
    for(int i=0; i<v[nod].size() && gasit==1; i++)
    {
        int vecin=v[nod][i].first;
        int cost=v[nod][i].second;
        if(c+cost<0 && vecin==1)
            gasit=1;
        if(c+cost<0 && a[vecin]==0)
            p(vecin, c+cost);
    }
    a[nod]=0;
}

int test()
{
    p(1, 0);
    if(gasit==1)
        return 1;
    else
        return 0;
}

void parc(int x)
{
    dist[x]=0;
    a[x]=1;
    q.push(x);
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        a[nod]=0;
        for(int i=0; i<v[nod].size(); i++)
        {
            int vecin=v[nod][i].first;
            int cost=v[nod][i].second;
            if(dist[nod]+cost<dist[vecin])
            {
                dist[vecin]=dist[nod]+cost;
                if(!a[vecin])
                {
                    q.push(vecin);
                    a[vecin]=1;
                }
            }
        }
    }
}

int main()
{
    f>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int x, y, c;
        f>>x>>y>>c;
        v[x].push_back(make_pair(y, c));
    }
    for(int i=1; i<=n; i++)
        dist[i]=2e9;
    if(test())
        g<<"Ciclu negativ!";
    else
    {
        parc(1);
        for(int i=2; i<=n; i++)
            g<<dist[i]<<" ";
    }
    return 0;
}