Cod sursa(job #2794340)

Utilizator bianca_voicuBianca Voicu bianca_voicu Data 4 noiembrie 2021 18:02:38
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.21 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

ifstream f("bfs.in");
ofstream g("bfs.out");


class Graph {
private:
    int _n, _m;
    vector<int> _list[100001];

public:
    Graph(int nodes, int edges) : _n(nodes), _m(edges) {}

    void addEdges();

    vector<int> bfs(int start);

};

void Graph::addEdges() {
    int x, y, i;
    for (i = 0; i < _m; i++) {
        f >> x >> y;
        _list[x].push_back(y);
    }
}

vector<int> Graph::bfs(int start) {
    queue<int> q;
    vector<int> ans;
    ans.resize(_n + 1);
    for (int i = 1; i <= _n; i++) {
        ans[i] = -1;
    }

    q.push(start);
    ans[start] = 0;
    while (!q.empty()) {
        int node = q.front();

        for (int i = 0; i < _list[node].size(); i++) {
            if (ans[_list[node][i]] == -1) {
                q.push(_list[node][i]);
                ans[_list[node][i]] = ans[node] + 1;
            }
        }
        q.pop();
    }

    return ans;
}


int main() {
    int n, m, s, i;
    f >> n >> m >> s;

    Graph gr(n, m);
    gr.addEdges();

    vector<int> ans = gr.bfs(s);
    for (i = 1; i <= n; i++) {
        g << ans[i] << " ";
    }

    f.close();
    g.close();
    return 0;
}