Cod sursa(job #3197479)

Utilizator Iustin2812Ion Iustin Ciprian Iustin2812 Data 26 ianuarie 2024 22:12:12
Problema BFS - Parcurgere in latime Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.09 kb
#include <iostream>
#include <vector>
#include <queue>
#include <fstream>

using namespace std;

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

vector<int> l[1000001];

void bfs(int start, int n, int p, vector<int>& distances) {
    vector<bool> visited(n + 1, false);
    queue<int> q;

    visited[start] = true;
    distances[start] = 0;
    q.push(start);

    while (!q.empty()) {
        int current = q.front();
        q.pop();

        for (int node : l[current]) {
            if (!visited[node]) {
                visited[node] = true;
                distances[node] = distances[current] + 1;
                q.push(node);
            }
        }
    }

    if (distances[p] == 0 && p != start) {
        fout << "-1 ";
    } else {
        fout << distances[p] << " ";
    }
}

int main() {
    int m, n, p;
    fin >> n >> m >> p;

    int x, y;
    for (int i = 1; i <= m; i++) {
        fin >> y >> x;
        l[x].push_back(y);
    }

    for (int i = 1; i <= n; i++) {
        vector<int> distances(n + 1, -1); // Initialize distances to -1
        bfs(i, n, p, distances);
    }

    return 0;
}