Cod sursa(job #1164867)

Utilizator rares96cheseliRares Cheseli rares96cheseli Data 2 aprilie 2014 12:40:56
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.01 kb
#include <fstream>
#include <vector>
#include <queue>
#define y first
#define c second
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");

typedef pair<int, int> edge;
int N, M, x, y, c, used[50005], sursa, D[50002];
vector < edge > G[50005];
queue < int > Q;
bool inQ[50002];

int main()
{
    f>>N>>M; sursa=1;
    for (int i=1; i<=M; ++i)
        f>>x>>y>>c, G[x].push_back(edge(y, c));

    for (int i=1; i<=N; ++i) D[i]=(1<<30);
    D[sursa]=0; inQ[sursa]=1; Q.push(sursa);
    while (Q.size())
    {
        int nod=Q.front(); Q.pop();
        inQ[nod]=0; ++used[nod];
        if (used[nod]==N) { g<<"Ciclu negativ!"; return 0; }
        vector <edge>::iterator it=G[nod].begin();
        for (; it!=G[nod].end(); ++it)
            if (D[it->y]>D[nod]+it->c)
            {
                D[it->y]=D[nod]+it->c;
                if (!inQ[it->y]) Q.push(it->y), inQ[it->y]=1;
            }
    }
    for (int i=2; i<=N; ++i)
        g<<D[i]<<' ';
    return 0;
}