Cod sursa(job #1412497)

Utilizator VictoriaNevTascau Victoria VictoriaNev Data 1 aprilie 2015 12:25:39
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.05 kb
#include <vector>
#include <fstream>
#include <queue>
using namespace std;
const int NMAX=50001;
const int inf=(1<<20);
vector< pair<int,int> > g[NMAX];
int d[NMAX];
queue<int> q;
int n, m, a, b, c, i, v[NMAX];
void init()
{
    for(i=2; i<=n; i++)
        d[i]=inf;
}
int bellmanford()
{
    init();
    int i, j, k, x;
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        v[x]++;
        if(v[x]>=n)
            return -1;
        for(vector< pair<int,int> >::iterator it=g[x].begin(); it!=g[x].end(); it++)
            if (d[it->first]>d[x]+it->second)//relax
            {
                d[it->first]=d[x]+it->second;
                q.push(it->first);
            }
    }
    return 1;
}
int main()
{
    ifstream in("bellmanford.in");
    ofstream out("bellmanford.out");
    in>>n>>m;
    for(i=1; i<=m; i++)
    {
        in>>a>>b>>c;
        g[a].push_back(make_pair(b,c));
    }
    q.push(1);
    if(bellmanford()<0)
        out<<"Ciclu negativ!\n";
    else
    {
        for(i=2; i<=n; i++)
            out<<d[i]<<' ';
    }
    return 0;
}