Cod sursa(job #2501538)

Utilizator coculescugabiCoculescu Gabriel coculescugabi Data 29 noiembrie 2019 20:28:58
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.57 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int NMax = 50005;
const int oo = (1 << 30); // max int

int N,M;
int D[NMax];
int viz[NMax];
bool Inqueue[NMax];

vector< pair<int, int> > G[NMax];
queue <int> Queue;

void Read() {
fin >> N >> M;
    for(int i = 1; i <= M; i++) {
        int x, y, c;
        fin >> x >> y >> c;
        G[x].push_back(make_pair(y,c));
    }
}

bool bellmanford(int s) {
    for(int i = 1; i <= N; i++) {
        viz[i] = 0;
        Inqueue[i] = false;
        D[i] = oo;
    }
    D[s] = 0;
    Queue.push(s);
    Inqueue[s] = true;

    while(!Queue.empty()) {
        int NodCurrent = Queue.front();
        viz[NodCurrent]++;
        //cout<< viz[NodCurrent] << endl;
        if(viz[NodCurrent] >= N)
            return false;
        Queue.pop();
        Inqueue[NodCurrent] = false;
        for(unsigned int i = 0; i < G[NodCurrent].size(); i++) {
            int Neighbour = G[NodCurrent][i].first;
            int Cost = G[NodCurrent][i].second;
            if(D[NodCurrent] + Cost < D[Neighbour]) {
                D[Neighbour] = D[NodCurrent] + Cost;
                if(Inqueue[Neighbour] == false)
                    Queue.push(Neighbour);
                    Inqueue[Neighbour] = true;
            }
        }
    }
    return true;
}

void Write() {
    if(bellmanford(1)) {
        for(int i = 2; i <= N; i++)
            fout<<D[i]<<" ";
    }
    else
      fout<<"Ciclu negativ!";

}

int main() {
    Read();
    Write();

    return 0;
}