Cod sursa(job #3318262)

Utilizator PaulTPaul Tirlisan PaulT Data 27 octombrie 2025 18:44:58
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.22 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

using VI = vector<int>;
using PI = pair<int, int>;
using VP = vector<PI>;
using VVP = vector<VP>;

constexpr int Inf = 0x3f3f3f3f;
int n, m;
VVP G;
VI d;

void Read();
void Dijkstra(int x, VI& d);
void Write();

int main()
{
    Read();
    Dijkstra(1, d);
    Write();
}

void Read()
{
    ifstream fin("dijkstra.in");
    fin >> n >> m;
    G = VVP(n + 1);
    
    int x, y, w;
    for (int i = 0; i < m; ++i)
    {
        fin >> x >> y >> w;
        G[x].emplace_back(y, w);
    }
    fin.close();
}

void Dijkstra(int x, VI& d)
{
    d = VI(n + 1, Inf);
    priority_queue<PI, VP, greater<PI>> q;
    
    d[x] = 0;
    q.emplace(0, x);
    int dx;
    while (!q.empty())
    {
        dx = q.top().first;
        x = q.top().second;
        q.pop();
        if (d[x] < dx)
            continue;
        
        for (const auto& edge: G[x])
        {
            auto [y, w] = edge;
            if (d[x] + w < d[y])
            {
                d[y] = d[x] + w;
                q.emplace(d[y], y);
            }
        }
    }
}

void Write()
{
    ofstream fout("dijkstra.out");
    for (int i = 2; i <= n; ++i)
        fout << d[i] << ' ';
    fout.close();
}