Cod sursa(job #3256840)

Utilizator AsandeiStefanAsandei Stefan-Alexandru AsandeiStefan Data 16 noiembrie 2024 10:44:19
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.32 kb
#include <algorithm>
#include <fstream>
#include <utility>
#include <vector>
#include <bitset>
#include <queue>

using namespace std;

const int nmax = 50050;
const int inf = 0x3f3f3f;

ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

int n, m, x, y, c;
vector<pair<int, int> > g[nmax+1];
vector<int> dist(nmax + 1, inf);

struct cmp {
    inline bool operator()(const int i, const int j) {
        return dist[i] > dist[j];
    }
};

void dijkstra(int source) {
    priority_queue<int, vector<int>, cmp> q;
    bitset<nmax> visited;

    dist[source] = 0;
    q.push(source);

    while(!q.empty()) {
        int node = q.top();
        q.pop();
        visited[node] = false;

        for(auto it = g[node].begin(); it < g[node].end(); ++it) {
            if(dist[node] + (*it).second < dist[(*it).first]) {
                dist[(*it).first] = dist[node] + (*it).second;
                if(!visited[(*it).first]) {
                    q.push((*it).first);
                    visited[(*it).first] = true;
                }
            }
        }
    }

}

int main() {
    fin >> n >> m;
    while (fin >> x >> y >> c) {
        g[x].push_back({y, c});
    }

    dijkstra(1);

    for (int i = 2; i <= n; i++) {
        if(dist[i] == inf)
            fout << 0 << ' ';
        else
            fout << dist[i] << ' ';
    }
    return 0;
}