Cod sursa(job #1118627)

Utilizator manutrutaEmanuel Truta manutruta Data 24 februarie 2014 12:19:24
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.39 kb
#include <cstring>
#include <iostream>
#include <fstream>
#include <bitset>
#include <vector>
#include <queue>
using namespace std;

#define MAXN 50005
#define INF 0x3f3f3f3f

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

FILE* f = fopen("dijkstra.in", "r");
FILE* g = fopen("dijkstra.out", "w");

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

int dijkstra(int nod, int* dist)
{
    for (int i = 1; i <= n; i++) {
        dist[i] = INF;
    }
    viz.reset();

    dist[nod] = 0;
    pq.push(make_pair(0, nod));
    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()
{
    fscanf(f, "%d %d\n", &n, &m);
    for (int i = 1, x, y, c; i <= m; i++) {
        fscanf(f, "%d %d %d\n", &x, &y, &c);
        G[x].push_back(make_pair(y, c));
    }

    dijkstra(1, dist);

    for (int i = 2; i <= n; i++) {
        fprintf(g, "%d ", (dist[i] == INF) ? (0) : (dist[i]));
    }

    return 0;
}