Cod sursa(job #1567017)

Utilizator mariapascuMaria Pascu mariapascu Data 12 ianuarie 2016 21:06:28
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 kb
#include <fstream>
#include <vector>
#include <set>
using namespace std;

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

const int INF = 0x3f3f3f3f;
int n, m;
vector<vector<pair<int, int>>> G;
vector<int> d;

void Read();
void Dijkstra();
void Write();

int main() {
    Read();
    Dijkstra();
    Write();
    fin.close();
    fout.close();
    return 0;
}

void Dijkstra() {
    set<pair<int, int>> S;
    d[1] = 0;
    S.insert({0, 1});
    int x, dx, y, dxy;
    while (!S.empty()) {
        x = S.begin()->second;
        dx = S.begin()->first;
        S.erase(S.begin());
        for (auto e : G[x]) {
            y = e.first; dxy = e.second;
            if (d[y] > d[x] + dxy) {
                d[y] = d[x] + dxy;
                S.insert({d[y], y});
            }
        }
    }
}

void Write() {
    for (int i = 2; i <= n; i++)
        if (d[i] == INF) fout << "0 ";
        else fout << d[i] << ' ';
}

void Read() {
    fin >> n >> m;
    G = vector<vector<pair<int, int>>>(n + 1);
    d = vector<int>(n + 1, INF);
    for (int i = 1, x, y, w; i <= m; i++) {
        fin >> x >> y >> w;
        G[x].push_back({y, w});
    }
}