Cod sursa(job #1094490)

Utilizator manutrutaEmanuel Truta manutruta Data 29 ianuarie 2014 14:47:24
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.29 kb
#include <cstring>
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
using namespace std;

#define inf 0x3f3f3f3f
#define MAXN 50005

typedef vector< pair<int, int> >::iterator iter;

ifstream f("dijkstra.in");
ofstream g("dijkstra.out");

int n, m;
vector< pair<int, int> > G[MAXN];
priority_queue< pair<int, int> > pq;
bitset<MAXN> viz;
int dist[MAXN];

void dijkstra() {
    memset(dist, 0x3f, sizeof(dist));
    viz.reset();

    dist[1] = 0;
    pq.push(make_pair(0, 1));
    while (!pq.empty()) {
        int nd = pq.top().second;
        pq.pop();

        if (viz[nd] == true) {
            continue;
        }
        viz[nd] = true;

        for (iter it = G[nd].begin(); it != G[nd].end(); it++) {
            if (dist[it->first] > dist[nd] + it->second) {
                dist[it->first] = dist[nd] + it->second;
                pq.push(make_pair(-dist[it->first], it->first));
            }
        }
    }
}

int main()
{
    f >> n >> m;
    for (int i = 1; i <= m; i++) {
        int x, y, c;
        f >> x >> y >> c;
        G[x].push_back(make_pair(y, c));
    }

    dijkstra();

    for (int i = 2; i <= n; i++) {
        g << ((dist[i] == inf) ? (0) : (dist[i])) << ' ';
    }

    return 0;
}