Cod sursa(job #2243715)

Utilizator MarianConstantinMarian Constantin MarianConstantin Data 21 septembrie 2018 11:35:04
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define N 100010

using namespace std;

int sizes[N], visited[N], distances[N];
vector<int> l[N];

void BFS(int start)
{
    int node;
    queue<int> q;
    q.push(start);
    distances[start]=1;
    visited[start]=1;
    while(!q.empty())
    {
        node=q.front();
        for(int i=0; i<sizes[node]; i++)
            if (!visited[l[node][i]])
            {
                q.push(l[node][i]);
                visited[l[node][i]]=1;
                distances[l[node][i]]=distances[node]+1;
            }
        q.pop();
    }
}

int main()
{
    ifstream fin("bfs.in");
    ofstream fout("bfs.out");
    int n, m, s, x, y;
    fin >> n >> m >> s;
    for (int i=1; i<=m; i++)
    {
        fin >> x >> y;
        l[x].push_back(y);
    }
    for (int i=1; i<=n; i++)
        sizes[i]=l[i].size();
    BFS(s);
    for (int i=1; i<=n; i++)
        fout << distances[i]-1 << " ";
    return 0;
}