Cod sursa(job #1929393)

Utilizator MaligMamaliga cu smantana Malig Data 17 martie 2017 16:11:59
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.47 kb
#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <limits.h>

using namespace std;
ifstream in("bellmanford.in");
ofstream out("bellmanford.out");

const int NMax = 5e4 + 5;
const int inf = 1e9;

int N,M;
int dist[NMax],nrInQueue[NMax];
bool inQueue[NMax];

struct elem {
    int y,c;
    elem() {}
    elem(int a,int b) {
        y = a;
        c = b;
    }
};
vector<elem> v[NMax];

int main() {
    in>>N>>M;
    for (int i=1;i<=M;++i) {
        int x,y,c;
        in>>x>>y>>c;
        elem e(y,c);
        v[x].push_back(e);
    }

    for (int i=2;i<=N;++i) {
        dist[i] = inf;
    }
    dist[1] = 0;

    queue<int> Q;
    Q.push(1);
    while(!Q.empty()) {
        int nod = Q.front();
        Q.pop();
        inQueue[nod] = false;
        ++nrInQueue[nod];
        if (nrInQueue[nod] == N) {
            out<<"Ciclu negativ!";
            return 0;
        }

        vector<elem>::iterator it;
        for (it = v[nod].begin();it < v[nod].end();++it) {
            int next = it->y, cost = it->c;
            if (dist[next] > dist[nod] + cost) {
                dist[next] = dist[nod] + cost;
                if (!inQueue[next]) {
                    inQueue[next] = true;
                    Q.push(next);
                }
            }
        }
    }

    for (int i=2;i<=N;++i) {
        out<<dist[i]<<' ';
    }

    in.close();out.close();
    return 0;
}