Cod sursa(job #1906578)

Utilizator AlexNiuclaeNiculae Alexandru Vlad AlexNiuclae Data 6 martie 2017 15:01:38
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.2 kb
#include <bits/stdc++.h>

using namespace std;

const int nmax = 5e4 + 10;
const int inf = 0x3f3f3f3f;

int n, m;
int D[nmax];
vector < pair < int, int > > g[nmax];

void input() {
    scanf("%d %d", &n, &m);
    for (int i = 1; i <= m; ++i) {
        int x, y, z;
        scanf("%d %d %d", &x, &y, &z);

        g[x].push_back({y, z});
        g[y].push_back({x, z});
    }
}

void run_dijkstra() {
    priority_queue < pair < int, int >, vector < pair < int, int > >, greater < pair < int, int > > > pq;
    memset(D, inf, sizeof(D));

    D[1] = 0;
    pq.push({0, 1});

    while (pq.size()) {
        int node, cost; tie(cost, node) = pq.top(); pq.pop();
        if (cost != D[node]) continue;

        for (auto &it: g[node]) {
            if (cost + it.second >= D[it.first]) continue;

            D[it.first] = cost + it.second;
            pq.push({D[it.first], it.first});
        }
    }
}

void output() {
    for (int i = 2; i <= n; ++i)
        (D[i] == inf) ? printf("0 ") : printf("%d ", D[i]);
}

int main() {
    freopen("dijkstra.in","r",stdin);
    freopen("dijkstra.out","w",stdout);

    input();
    run_dijkstra();
    output();

    return 0;
}