Cod sursa(job #3256343)

Utilizator adimiclaus15Miclaus Adrian Stefan adimiclaus15 Data 14 noiembrie 2024 10:45:57
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.45 kb
#include <bits/stdc++.h>

using namespace std;

const int NMAX = 5e4;
const int INF = 1e9;
vector< pair<int, int> > G[NMAX + 1];
int d[NMAX + 1]; //d[i] = distanta minima de la 1 la i
int vis[NMAX + 1];

int main() {
    ifstream f("dijkstra.in");
    ofstream g("dijkstra.out");
    int n, m;
    f >> n >> m;
    for(int i = 1; i <= m; i++) {
        int x, y, c;
        f >> x >> y >> c;
        //G[x].push_back(make_pair(y, c));
        G[x].push_back({y, c});
    }
    for(int i = 1; i <= n; i++) {
        d[i] = INF;
    }
    d[1] = 0;
    //O(mlogn)
    //set< pair<int, int> > s; //(distanta, nod)
    priority_queue< pair<int, int>, vector< pair<int, int> >, greater < pair<int, int> > > s;
    s.push({d[1], 1});
    while(!s.empty()) {
        //auto it = s.begin();
        int node = s.top().second;
        //s.erase(it);
        s.pop();
        if(vis[node]) {
            continue;
        }
        vis[node] = 1;
        for(auto next : G[node]) {
            int vecin = next.first;
            int cost_muchie = next.second;
            if(!vis[vecin] && d[vecin] > d[node] + cost_muchie) {
                //s.erase({d[vecin], vecin});
                d[vecin] = d[node] + cost_muchie;
                s.push({d[vecin], vecin});
            }
        }
    }
    for(int i = 2; i <= n; i++) {
        if(d[i] == INF) {
            d[i] = 0;
        }
        g << d[i] << ' ';
    }
    return 0;
}