Cod sursa(job #2354693)

Utilizator DanSDan Teodor Savastre DanS Data 25 februarie 2019 15:07:20
Problema Algoritmul Bellman-Ford Scor 30
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.3 kb
#include <iostream>
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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

const int N = 50001;
const int M = 250001;
const int INF = 1001;

int n, m, x, y, c, d[N], nrq[N];
bool inq[N];
vector < pair<int, int> > a[N];
queue <int> q;

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

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

    q.push(1);
    inq[1] = true;
    nrq[1]++;
    d[1] = 0;
    pair<int, int> p;
    while(!q.empty())
    {
        x = q.front();
        q.pop();
        inq[x] = false;
        //for(auto p: a[x])
        for (int i = 0; i < a[x].size(); i++)
        {
            p = a[x][i];
            y = p.first;
            c = p.second;
            if(d[x] + c < d[y])
            {
                d[y] = d[x] + c;
                if(!inq[y])
                {
                    q.push(y);
                    inq[y] = true;
                    nrq[y]++;
                    if(nrq[y] > n)
                    {
                        out<<"Ciclu negativ!";
                        return 0;
                    }
                }
            }
        }
    }
    for(int i=2; i<=n; i++)
        out<<d[i]<<' ';
    return 0;
}