Cod sursa(job #566845)

Utilizator BalcauIonutFMI-Balcau Ionut BalcauIonut Data 29 martie 2011 12:36:07
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp Status done
Runda Arhiva educationala Marime 1.38 kb
#include <iostream>
#include <vector>
#include <cstdio>
#include <queue>
using namespace std;
const int INF=1<<30;

int n,m;
vector< pair<int,int> > a[50001];
int dist[50001];
int cycle[50001];
void readData(){
    int i,x,y,c;
    freopen("bellmanford.in","r",stdin);
    scanf("%d %d",&n,&m);
    for(i=0;i<m;++i){
        scanf("%d %d %d",&x,&y,&c);
        a[x].push_back(make_pair(y,c));
    }
}

bool bellmanFord(){
    queue< int > q; int x,i;
    for(i=2;i<=n;++i)
        dist[i]=INF;
    dist[1]=0;
    q.push(1);
    cycle[1]=0;
    while(!q.empty()){
        x=q.front();
        q.pop();
        for(i=0;i<a[x].size();++i)
            if(dist[x]+a[x][i].second<dist[a[x][i].first]){
                dist[a[x][i].first]=dist[x]+a[x][i].second;
                q.push(a[x][i].first);
                ++cycle[a[x][i].first];
                if(cycle[a[x][i].first]>=n)
                    return false;
            }
    }
    return true;
}

void writeData(){
    int i;
    freopen("bellmanford.out","w",stdout);
    if(bellmanFord())
        for(i=2;i<=n;++i)
            printf("%d ",dist[i]);
    else printf("Ciclu Negativ!\n");
}

int main(){
    readData();
    writeData();

   /* int i,j;
    for(i=1;i<=n;++i)
        for(j=0;j<a[i].size();++j)
        printf("%d %d %d\n",i,a[i][j].first,a[i][j].second);
    */
    return 0;
}