Cod sursa(job #2374522)

Utilizator PaulTPaul Tirlisan PaulT Data 7 martie 2019 19:09:19
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.39 kb
#include <fstream>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

struct Pair {
    int node, dist;
    bool operator < (const Pair& a) const
    {
        return dist > a.dist;
    }
};

using VP = vector<Pair>;
using VVP = vector<VP>;
using VI = vector<int>;

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

void Dijkstra(int x, VI& d)
{
    priority_queue<Pair> Q;
    d = VI(n + 1, Inf);
    d[x] = 0;
    Q.push({x, 0});
    int dx, y, w;
    while (!Q.empty())
    {
        x = Q.top().node;
        dx = Q.top().dist;
        Q.pop();
        if (dx > d[x])
            continue;
        for (const Pair& p : G[x])
        {
            y = p.node;
            w = p.dist;
            if (d[y] > d[x] + w)
            {
                d[y] = d[x] + w;
                Q.push({y, d[y]});
            }
        }
    }
}

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].push_back({y, w});
    }
    fin.close();
}