Cod sursa(job #876837)

Utilizator swim406Teudan Adina swim406 Data 12 februarie 2013 10:50:53
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.06 kb
#include <stdio.h>
#include <vector>
#include <queue>
 
#define NMAX 50001
#define INF (1 << 30)
 
using namespace std;

 
vector < pair <int, int> > G[NMAX];
queue <int> q;
 
int N;
int d[NMAX];
int viz[NMAX];

int y, c, m, i, x, M;

void read() {
	freopen ("bellmanford.in", "r", stdin);
	scanf ("%d %d", &N, &M);
	for (int i = 1; i <= M; ++i) {
		scanf("%d %d %d", &x, &y, &c);
		G[x].push_back(make_pair(y, c));
	}
}

int solve(int v) {
	for (int i = 1; i <= N; ++i)
		d[i] = INF;
	d[v] = 0;
	q.push(v);
	while (!q.empty()) {
		x = q.front();
		q.pop();
		m = G[x].size();
		for (i = 0; i < m; ++i) {
			y = G[x][i].first;
            c = G[x][i].second;
			if (d[y] > d[x] + c) {
				d[y] = d[x] + c;
				q.push(y);
				++viz[x];
			}
		}
		if (viz[x] > N)
			return 0;
	}
	return 1;
}

int main () {
	freopen ("bellmanford.out", "w", stdout);
	read();
	if (solve(1)) 
		for (i = 2; i <= N; ++i)
			if (d[i] != INF) 
				printf ("%d ", d[i]);
			else printf("0");
	else 
		printf("Ciclu negativ!\n");
	return 0;
}