Cod sursa(job #2922834)

Utilizator RobertlelRobert Robertlel Data 10 septembrie 2022 11:58:59
Problema Algoritmul Bellman-Ford Scor 15
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.03 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

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

int viz[50005],st[50005],i,j,p,k,cycle,s,n,x,y,c,m,dist[50005];

int inf=2e9;

vector<pair<int,int>>v[50005];

queue<int>coada;

void dfs(int nod)
{
    viz[nod]=1;
    k++;
        st[k]=nod;
        for(int i=0;i<v[nod].size();i++)
        {
            int vecin=v[nod][i].first;
            int cost=v[nod][i].second;
            if(viz[vecin]==0)
            {
                s=s+cost;
                dfs(vecin);
            }
            else
                if(viz[vecin]==1&&vecin==st[1])
            {
                s=s+cost;
                if(s<0)
                cycle=1;
            }
        }

}

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

int main()
{
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>c;
        v[x].push_back(make_pair(y,c));

    }
    for(i=1;i<=n;i++)
    {
        s=0;
        if(cycle==0)
        dfs(i);
        if(cycle==1)
        {
            g<<"Ciclu negativ";
            break;
        }
            for(j=1;j<=k;j++)
                st[j]=0;
            for(p=1;p<=n;p++)
                viz[p]=0;
                k=0;
    }
    for(i=1;i<=n;i++)
        dist[i]=inf;
        if(cycle==0)
        {

    djs(1);
    if(cycle==0)
    {
       for(i=2;i<=n;i++)
           g<<dist[i]<<" ";
    }
        }
    return 0;
}