Cod sursa(job #3285679)

Utilizator StefanRaresStefan Rares StefanRares Data 13 martie 2025 12:41:22
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.74 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream f("dijkstra.in");
ofstream g("dijkstra.out");
const int NMAX = 50001, INF = 1 << 29;
struct muchie
{
    int y, w;
    muchie(int yy = 0, int ww = 0): y(yy), w(ww) {}
};
int N, M, D[NMAX];
bool InQ[NMAX];///InQ[i] = 1 <==> nodul i este in coada
class Comp ///pt coada cu prioritate
{
public:
    bool operator()(int a, int b) const
    {
        return D[a] > D[b];
    }
};
vector<muchie> G[NMAX];
priority_queue<int, vector<int>, Comp> Q;
void citire()
{
    int x, y, c;
    f >> N >> M;
    for(int i = 1; i <= M; i++)
    {
        f >> x >> y >> c;
        G[x].push_back(muchie(y, c));
    }
}
void Dijkstra(int nod)
{
    int crt, cost;
    D[nod] = 0;
    InQ[nod] = 1;
    Q.push(nod);
    while(!Q.empty())
    {
        crt = Q.top(); ///Se extrage varful aflat la distanta minima fata de "nod"
        Q.pop();
        InQ[crt] = 0;
        ///Se parcurg arcele care poleaca din varful crt si se optimizeaza
        ///consturile drumurilor pentru varfurile care sunt extremitati finale
        ///ale acestor arce
        for(const muchie &mm : G[crt])
        {
            cost = D[crt] + mm.w;
            if(D[mm.y] > cost)
            {
                D[mm.y] = cost;
                if(!InQ[mm.y])
                {
                    Q.push(mm.y);
                    InQ[mm.y] = 1;
                }
            }
        }
    }
}
int main()
{
    int i;
    citire();
    for(i = 1; i <= N; i++)
        D[i] = INF;
    Dijkstra(1);
    for(i = 2; i <= N; i++)
        if(D[i] == INF) g << "0 ";
        else g << D[i] << ' ';
    f.close();
    g.close();
    return 0;
}