Cod sursa(job #1376098)

Utilizator CosminRusuCosmin Rusu CosminRusu Data 5 martie 2015 15:58:32
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.32 kb
#include <iostream>
#include <vector>
#include <algorithm>
#include <bitset>
#include <fstream>
#include <queue>
#include <string.h>

using namespace std;

ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");

const int maxn = 50005;
const int oo = 0x3f3f3f3f;

int n, m, dist[maxn], inqs[maxn];
vector <pair<int, int> > g[maxn];
bitset <maxn> inq;
queue <int> q;

inline void bellmanford() {
    memset(dist, oo, sizeof(dist));
    dist[1] = 0;
    q.push(1);
    inq[1] = 1;
    while(!q.empty()) {
        int node = q.front();
        q.pop();
        inq[node] = 0;
        for(vector <pair<int, int> > :: iterator it = g[node].begin() ; it != g[node].end() ; ++ it)
            if(dist[it->first] > dist[node] + it->second) {
                dist[it->first] = dist[node] + it->second;
                if(inq[it->first])
                    continue;
                if(++ inqs[it->first] > n) {
                    fout << "Ciclu negativ!\n";
                    return ;
                }
                inq[it->first] = 1;
                q.push(it->first);
            }
    }
    for(int i = 2 ; i <= n ; ++ i)
        fout << dist[i] << ' ';
}

int main() {
    fin >> n >> m;
    for(int i = 1 ; i <= m ; ++ i) {
        int x, y, z;
        fin >> x >> y >> z;
        g[x].push_back(make_pair(y, z));
    }
    bellmanford();
}