Cod sursa(job #2280219)

Utilizator pioneer22Semeniuc Calin pioneer22 Data 10 noiembrie 2018 12:47:46
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.59 kb
#include <algorithm>
#include <fstream>
#include <cstring>
#include <cassert>
#include <vector>
#include <set>
using namespace std;
///INF = 0x3f3f3f3f;
vector < pair <int, int > > G[50005];

int dist[50005];

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

    int n,m,i,from,to,cost;
    fscanf (f,"%d%d",&n,&m);
    assert(1 <= n && n <= 50000);
    assert(1 <= m && m <= 250000);

    for (i=0;i<m;i++)
    {
        fscanf (f,"%d%d%d",&from,&to,&cost);
        assert(1 <= from && from <= n);
        assert(1 <= to && to <= n);
        assert(0 <= cost && cost <= 20000);
        G[from].push_back(make_pair(to, cost));
    }

    memset(dist, 0x3f3f3f3f, sizeof dist);
    dist[1] = 0;
    set< pair< int, int > > h;
    h.insert(make_pair(0, 1));
    while (!h.empty()) {
        int node = h.begin()->second;
        int d = h.begin()->first;
        h.erase(h.begin());

        for (vector < pair <int, int > > ::iterator it = G[node].begin(); it != G[node].end(); ++it) {
            int to = it->first;
            int cost = it->second;
            if (dist[to] > dist[node] + cost) {
                if (dist[to] != 0x3f3f3f3f) {
                    h.erase(h.find(make_pair(dist[to], to)));
                }
                dist[to] = dist[node] + cost;
                h.insert(make_pair(dist[to], to));
            }
        }
    }

    for (i = 2; i <= n; ++i) {
        if (dist[i] == 0x3f3f3f3f) {
            dist[i] = 0;
        }
        fprintf (g,"%d ",dist[i]);
    }
    fprintf (g,"\n");
}