Cod sursa(job #3197482)

Utilizator Iustin2812Ion Iustin Ciprian Iustin2812 Data 26 ianuarie 2024 22:15:27
Problema BFS - Parcurgere in latime Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.12 kb
#include <iostream>
#include <vector>
#include <fstream>

using namespace std;

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

void bfs(int start, int n, int p, const vector<vector<int>>& graph, vector<int>& distances) {
    vector<int> queue;
    int front = 0, rear = 0;

    queue.push_back(start);
    distances[start] = 0;

    while (front <= rear) {
        int current = queue[front++];
        
        for (int node : graph[current]) {
            if (distances[node] == -1) {
                distances[node] = distances[current] + 1;
                queue.push_back(node);
                ++rear;
            }
        }
    }

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

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

    vector<vector<int>> graph(n + 1);
    int x, y;
    for (int i = 1; i <= m; i++) {
        fin >> y >> x;
        graph[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, graph, distances);
    }

    return 0;
}