Nivele2

#include    <iostream>
#include    <fstream>
#include    <vector>
#include    <algorithm>

using namespace std;

ifstream fin("nivele2.in");
ofstream fout("nivele2.out");

const int LIM = 100005;
int N, MaxLev;
bool beenThere[LIM];

vector < int > V[LIM], Level[LIM];

void DFS(int node, int level)
{
    beenThere[node] = true;
    Level[level].push_back(node);
    if(level > MaxLev) MaxLev = level;
    for(unsigned int i = 0; i < V[node].size(); i++)
    {
        int Target = V[node][i];
        if(!beenThere[Target])
            DFS(Target, level + 1);
    }
}

void Read()
{
    int x, y;
    fin >> N;
    for(int i = 1; i <= N; i++)
    {
        fin >> x >> y;
        V[x].push_back(y);
    }
    DFS(1,1);
    for(int i = 1; i <= MaxLev; i++)
    {
        fout << "nivelul " << i << ": ";
        //sort(Level[i].begin(), Level[i].end());
        for(unsigned int j = 0; j < Level[i].size(); j++)
            fout << Level[i][j] << " ";
        fout << "\n";
    }
}

int main()
{
    Read();
    return 0;
}