Cod sursa(job #2757056)

Utilizator ioana0211Ioana Popa ioana0211 Data 3 iunie 2021 19:04:43
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.36 kb
#include <iostream>
#include <fstream>
#include <queue>
#include <bits/stdc++.h>

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

int n, m, x, y, c;
vector<pair<int, int>> g[50001];
int d[50001], viz[50001], l[50001];
queue<int> q;

bool bellman_ford (int start_node)
{
    for(int i=1; i<=n; i++) d[i]=INT_MAX/2;
    d[start_node]=0; viz[start_node]=1;
    q.push(start_node);
    while(!q.empty())
    {
        int crt_node=q.front();
        q.pop();
        viz[crt_node]=0;
        l[crt_node]++;
        if(l[crt_node]>=n) return false;

        for(size_t i=0; i<g[crt_node].size(); i++)
        {
            int vecin=g[crt_node][i].first;
            int cost=g[crt_node][i].second;
            if(d[crt_node]+cost<d[vecin])
            {
                d[vecin]=d[crt_node]+cost;
                if(!viz[vecin]) {
                        q.push(vecin);
                        viz[vecin]=1;
                    }

            }
        }
    }
    return true;
}
int main()
{
    fin>>n>>m;
    while(fin>>x>>y>>c)
        g[x].push_back(make_pair(y, c));
    bool res=bellman_ford(1);
    if(res==0) fout<<"Ciclu negativ!";
    else for(int i=2; i<=n; i++){
        if(d[i]==INT_MAX/2)
            fout<<0<<" ";
        else
            fout<<d[i]<<" ";
    }
    return 0;
}