Cod sursa(job #3170056)

Utilizator zetef3Dediu Stefan zetef3 Data 16 noiembrie 2023 18:53:35
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.95 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

#define NMAX 100001

using namespace std;

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

int N,M,S;
vector<int> adj[NMAX];
queue<int> q;
vector<bool> used;
vector<int> d;

void read() {
    f >> N >> M >> S; S--;

    used.resize(N);
    d.resize(N);

    for (int i=1;i<=M;i++) {
        int x,y;
        f >> x >> y;
        x--; y--;
        adj[x].push_back(y);
    }
}

void bfs(int r) {
    q.push(r);
    used[r]=true;

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

        for (int u:adj[v]) {
            if (!used[u]) {
                used[u]=true;
                q.push(u);
                d[u]=d[v]+1;
            }
        }
    }
}

void afis() {
    for (int i=0;i<N;i++) {
        if (i==S) g << "0 ";
        else if (d[i]==0) g << "-1 ";
        else              g << d[i] << ' ';
    }
}

int main()
{
    read();
    bfs(S);
    afis();
    return 0;
}