Cod sursa(job #2136955)

Utilizator ifrimencoAlexandru Ifrimenco ifrimenco Data 20 februarie 2018 14:25:40
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.21 kb
#include <fstream>
#include <vector>
#include <utility>
#include <queue>
#include <iostream>
#define nmax 50005
#define INF (1 << 30)

using namespace std;

ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

vector <pair <int, int> >  v[nmax];
vector <int> cost (nmax, INF);

struct comp {
    bool operator() (const pair <int, int>  &a, const pair <int, int> &b) {
        return a.second > b.second;
    }
};

priority_queue <pair <int, int>, vector <pair <int, int> >, comp> q;


int main()
{
    int n, m, x, y, c;
    fin >> n >> m;
    for (; m; m--) {
        fin >> x >> y >> c;
        v[x].push_back(make_pair(y, c));
    }
    q.push(make_pair(1, 0));
    cost[1] = 0;
    while (!q.empty()) {
        x = q.top().first;
        c = q.top().second;
        q.pop();
        if (cost[x] != c) continue;

        for (auto it: v[x]) {
            if (c + it.second < cost[it.first]) {
                cost[it.first] = cost[x] + it.second;
                q.push(make_pair(it.first, cost[it.first]));
            }
        }
    }
    for (int i = 2; i <= n; ++i)
        if (cost[i] == INF) fout << 0 << " ";
        else fout << cost[i] << " ";

    return 0;
}