Cod sursa(job #2808045)

Utilizator rimihaiMihai Radu-Ioan rimihai Data 24 noiembrie 2021 15:05:15
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.22 kb
#include <bits/stdc++.h>

using namespace std;

#define INFINIT 0x3f3f3f3f

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

vector<pair<int,int>> g[50005];
int viz[50005];
int d[50005];
bool ok;

void bellmanFord(int startNod, int n)
{
    d[startNod]=0;
    priority_queue<pair<int,int>> q;
    q.push({0,startNod});
    while(!q.empty())
    {

        int nod=q.top().second;
        viz[nod]++;
        if(viz[nod]>=n)
        {
            fout<<"Ciclu negativ!";
            ok=0;
            return;
        }
        q.pop();
        for(auto vecin : g[nod])
        {
            if(d[nod]+vecin.second<d[vecin.first])
            {
                d[vecin.first]=d[nod]+vecin.second;
                q.push({-d[vecin.first],vecin.first});
            }
        }
    }
}

int main()
{
    int n,m;
    fin>>n>>m;
    ok=1;
    for(int i=1; i<=m; i++)
    {
        int a,b,cost;
        fin>>a>>b>>cost;
        g[a].push_back({b,cost});
    }

    for(int i=1; i<=n; i++)
        d[i]=INFINIT;

    bellmanFord(1,n);

    if(ok==1)
        for(int i=2; i<=n; i++)
            if(d[i]!=INFINIT)fout<<d[i]<<" ";
            else fout<<0<<" ";
    return 0;
}