Cod sursa(job #3030079)

Utilizator MihaiAlexDevMihai Alex MihaiAlexDev Data 17 martie 2023 15:04:46
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.69 kb
#include <fstream>
#include <vector>
#include <queue>
#include <iostream>
#include <algorithm>

using namespace std;

const int infinity = 1 << 30;

#define nMax 50005

int n,m;

vector <int> distanta(nMax);
vector <bool> inQueue(nMax);

vector <pair<int, int>> graf[nMax];

struct compare {
    bool operator()(int x, int y) {
        return distanta[x] > distanta[y];
    }
};

priority_queue<int, vector<int>, compare> coada;

void dijkstra (int nodStart) {
    for(int i = 1; i <= n; i++)
        distanta[i] = infinity;
    distanta[nodStart] = 0;
    coada.push(nodStart);
    inQueue[nodStart] = true;
    while (!coada.empty()) {
        int nodCurent = coada.top();
        coada.pop();
        inQueue[nodCurent] = false;
        for(unsigned i = 0; i < graf[nodCurent].size(); i++) {
            int vecin = graf[nodCurent][i].first;
            int cost = graf[nodCurent][i].second;
            if(distanta[nodCurent] + cost < distanta[vecin])
                distanta[vecin] = distanta[nodCurent] + cost;
            if(!inQueue[vecin]) {
                coada.push(vecin);
                inQueue[vecin] = true;
            }
        }
    }

}

void show() {
    ofstream out("dijkstra.in");
    for(int i = 2; i <= n; i++) {
        if (distanta[i] != infinity) {
            out << distanta[i] << " ";
        } else {
            out << 0 << " ";
        }
    }
}

void read() {
    ifstream in("dijkstra.in");
    in >> n >> m;
    for(int i = 1; i <= m; i++) {
        int x,y,cost;
        in >> x >> y >> cost;
        graf[x].push_back(make_pair(y,cost));
    }
}

int main() {
    read();
    dijkstra(1);
    show();
    return 0;
}