Cod sursa(job #2663964)

Utilizator CostinteoGrigore Costin Teodor Costinteo Data 27 octombrie 2020 18:01:00
Problema BFS - Parcurgere in latime Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.11 kb
#include <fstream>
#include <iostream>
#include <vector>
#include <iterator>
#include <queue>

std::vector <std::vector <int>> adj;

void read(int &n, int &node) {
    std::ifstream f("bfs.in");
    f >> n;
    adj.resize(n);
    int edges;
    f >> edges;
    f >> node;
    for (int i = 0; i < edges; i++) {
        int x, y;
        f >> x >> y;
        adj[x - 1].push_back(y - 1);
    }
    f.close();
}

void bf_search(int x, int n) {
    std::queue <int> q;
    std::vector <int> visited;
    std::vector <int> distance;

    visited.assign(n, 0);
    distance.assign(n, -1);

    visited[x] = 1;
    distance[x] = 0;
    q.push(x);
    while (!q.empty()) {
        for (std::vector<int>::iterator it = adj[q.front()].begin(); it != adj[q.front()].end(); it++) {
            if (!visited[*it]) {
                q.push(*it);
                distance[*it] = distance[q.front()] + 1;
            }
        }
        q.pop();
    }

    std::ofstream g("bfs.out");

    for (int dist : distance) {
        g << dist << " ";
    }

    g.close();
}

int main() {
    int n, x;
    read(n, x);
    bf_search(x - 1, n);
    return 0;
}