Cod sursa(job #1052500)

Utilizator TeoZamfirescuZamfirescu Teodora TeoZamfirescu Data 11 decembrie 2013 13:44:11
Problema Algoritmul Bellman-Ford Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.61 kb
#include<cstdio>
#include<utility>
#include<queue>
#include <vector>
#define NMAX 50005
#define inf 1000000000
using namespace std;

FILE *fin, *fout;

int n, m, x, y, c, cost;
vector<pair<int, int> > graf[NMAX];
queue <int> coada;
int dmin[NMAX], nr[NMAX], pred[NMAX];

void citire()
{
    int i;
    fin = fopen("bellmanford.in", "r");
    fscanf(fin, "%d%d", &n, &m);
    for(i = 1; i <= m; i++)
    {
        fscanf(fin, "%d%d%d", &x, &y, &cost);
        graf[x].push_back(make_pair(y, cost));
    }
}

bool bellman_ford()
{
    int i;
    for(i = 2; i <= n; i++)
    {
        dmin[i] = inf;
        pred[i] = 1;
    }
    coada.push(1);
    nr[1]++;
    while(!coada.empty())
    {
        x = coada.front();
        coada.pop();
        for(i = 0; i < graf[x].size(); i++)
        {
            y = graf[x][i].first;
            c = graf[x][i].second;
            if(dmin[y] > dmin[x] + c)
            {
                dmin[y] = dmin[x] + c;
                pred[y] = x;
                coada.push(y);
                nr[y]++;
                if(nr[y] == n)
                {
                    return false;
                }
            }
        }
    }
    return true;
}

void afisare()
{
    int i;
    fprintf(fout, " %d", dmin[2]);
    for(i = 3; i <= n; i++)
    {
        fprintf(fout, " %d", dmin[i]);
    }
    fprintf(fout, "\n");
}

int main()
{
    fout = fopen("bellmanford.out", "w");
    citire();
    if(bellman_ford() == false)
    {
        fprintf(fout, "Ciclu negativ!");
    }
    else
    {
        afisare();
    }
    return 0;
}