Cod sursa(job #1888337)

Utilizator PaulCbnCiobanu Paul PaulCbn Data 22 februarie 2017 01:26:41
Problema Algoritmul Bellman-Ford Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.61 kb
#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <windows.h>
#define NMAX 50005
#define MMAX 250005
#define inf 0x3f3f3f3f

using namespace std;

int N,M;
vector<pair<int,int> > graf[NMAX];
int viz[NMAX],used[NMAX],d[NMAX];


void citire()
{
    scanf("%d%d",&N,&M);
    for(int i=1;i<=M;i++)
    {
        int x,y,c;
        scanf("%d%d%d",&x,&y,&c);
        graf[x].push_back(make_pair(y,c));
    }
}

queue<int> q;


void bellman_ford()
{
    for(int i=2;i<=N;i++)
        d[i]=inf;

    viz[1]=used[1]=1;
    q.push(1);
    while(!q.empty())
    {
        int nod = q.front();
        q.pop();
        used[nod]=0;
        for(vector<pair<int,int> >::iterator ii = graf[nod].begin();ii!=graf[nod].end();ii++)
        {
            int nod_nou = ii->first;
            int cost = ii->second;
            if(cost + d[nod] < d[nod_nou])
            {
                d[nod_nou] = cost + d[nod];
                if(!used[nod_nou])
                {
                    q.push(nod_nou);
                    used[nod_nou]=1;
                    viz[nod_nou]++;
                    if(viz[nod_nou]==N)
                    {
                        printf("Ciclu negativ!");
                        exit(0);
                    }
                }
            }
        }
    }

}

void afisare()
{
    for(int i=2;i<=N;i++)
        printf("%d ",d[i]==inf?0:d[i]);
}

int main()
{
    freopen("bellmanford.in","r",stdin);
    freopen("bellmanford.out","w",stdout);
    citire();
    bellman_ford();
    afisare();


    return 0;
}