Cod sursa(job #2889821)

Utilizator robberttPopa Robert robbertt Data 13 aprilie 2022 13:11:08
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.43 kb
#include <iostream>
#include <vector>
#include <fstream>
#include <string.h>
#include <queue>

using namespace std;
 
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");
 
#define INF 10000000
 
int n, m, x, y, c;
int dist[51000];
int marked[51000];
vector < pair <int, int> > edges[251000];
queue <int> Q;
 
void input()
{
    fin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        fin >> x >> y >> c;
        edges[x].push_back({y,c});
	}
}
 
bool bellmanford(int start)
{
	memset(marked, 0, sizeof(marked));
    for(int i = 1; i <= n; i++)
        dist[i] = INF;
    dist[start] = 0;
    Q.push(start);
    while(!Q.empty())
    {
        int current_node = Q.front();
        Q.pop();
        marked[current_node]++;
        if(marked[current_node] >= n)
            return false;
        for(int i = 0; i < edges[current_node].size(); i++)
        {
            int next_node = edges[current_node][i].first;
            int cost = edges[current_node][i].second;
            if(dist[current_node] + cost < dist[next_node])
			{
                dist[next_node] = dist[current_node] + cost;
                Q.push(next_node);
            }
        }
    }
    return true;
}
 
int main()
{
    input();
    if(bellmanford(1) == false)
    {
        fout << "Ciclu negativ!";
    }
    else
        for(int i = 2; i <= n; i++)
            fout << dist[i] << " ";
    return 0;
}