Cod sursa(job #1846171)

Utilizator danyvsDan Castan danyvs Data 12 ianuarie 2017 12:01:15
Problema Algoritmul lui Dijkstra Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 1.66 kb
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>

using namespace std;

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

const int NMAX = 50001;

#define INF 2000000000

int n, m;
vector < vector < pair < int, int > > > V(NMAX);
int D[NMAX];

void read()
{
    int i, x, y, cost;
    fscanf(f, "%d%d", &n, &m);
    for (i = 1; i <= m; ++ i)
        {
         fscanf(f, "%d%d%d", &x, &y, &cost);
         V[x].push_back(make_pair(y, cost));
        }
}

void dijkstra(int source)
{
    int v, d, v2, cost, i;
    priority_queue < pair < int, int >, vector < pair < int, int > >, greater < pair < int, int > > > PQ;
    pair < int, int > top;
    vector < pair < int, int > > :: iterator it;
    for (i = 1; i <= n; ++ i)
        D[i] = INF;
    D[source] = 0;
    PQ.push(make_pair(source, 0));
    while (!PQ.empty())
        {
         top = PQ.top();
         PQ.pop();
         v = top.first;
         d = top.second;
         if (d <= D[v])
            {
             for (it = V[v].begin(); it != V[v].end(); ++ it)
                {
                 v2 = (*it).first;
                 cost = (*it).second;
                 if (D[v2] > D[v] + cost)
                    {
                     D[v2] = D[v] + cost;
                     PQ.push(make_pair(v2, D[v2]));
                    }
                }
            }
        }
}

void print()
{
    int i;
    for (i = 2; i <= n; ++ i)
        if (D[i] != INF)
            fprintf(g, "%d ", D[i]);
        else
            fprintf(g, "0 ");
}

int main()
{
    read();
    dijkstra(1);
    print();
    return 0;
}