Go: #include <bits/stdc++.h>
using namespace std;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int N     = 100;

int n, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

void dfs_visit(int u) {
  color[u] = GRAY;
  d[u]     = ++tt;
  for (int v = 0; v < n; v++) {
    if (M[u][v] == 0) continue;
    if (color[v] == WHITE) { dfs_visit(v); }
  }
  color[u] = BLACK;
  f[u]     = ++tt;
}

void dfs() {
  tt = 0;

  for (int u = 0; u < n; u++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int u = 0; u < n; u++) {
    printf("%d %d %d\n", u + 1, d[u], f[u]);
  }
}

int main() {
  int u, v, k;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }

  dfs();
}

C++: #include <iostream>
#include <ios>
#include <vector>
using namespace std;

void read_data(int n, vector<vector<int>> & Es){
    int u = 0, k = 0, v = 0;
    while (n--){
        cin >> u;
        cin >> k;
        while (k--){
            cin >> v;
            Es[u - 1].push_back(v - 1);
        }
    }
}

void display_result(int n, vector<int> & d, vector<int> & f)

{
    for (int i = 0; i != n; ++i){
        cout << i + 1 << ' ' << d[i] << ' ' << f[i] << endl;
    }
}

void dfs(int node, int & time, vector<vector<int>> & Es, vector<int> & d, vector<int> & f ){
    if (d[node]) return;
    d[node] = time;
    ++time;
    for (auto next_node : Es[node]){
        dfs(next_node, time, Es, d, f);
    }
    f[node] = time;
    ++time;
}

int main()
{
    ios::sync_with_stdio(false);
    int n = 0;
    cin >> n;
    vector< vector<int> > Es(n);
    vector<int> d(n, 0);
    vector<int> f(n, 0);
    read_data(n, Es);
    int time = 1;
    for (int node = 0; node != n; ++node) dfs(node, time, Es, d, f);
    display_result(n, d, f);
    
    return 0;
}

C++: #include <queue>
#include <map>
#include <cstdio>
#include <algorithm>
using namespace std;
map<int,vector<int> >a;
map<int,int>m;
vector<pair<int,pair<int,int> > >v;
int T;
void D(int k){
	m[k]=1;
	int t=T;
	for(int i=0;i<a[k].size();i++)if(!m[a[k][i]])++T,D(a[k][i]);
	T++;
	v.push_back(make_pair(k,make_pair(t,T)));
}
main(){
	int i,j,k,N,n=0;
	for(scanf("%d",&N);n<N;n++)for(scanf("%d%d",&i,&k);k--;a[i].push_back(j))scanf("%d",&j);
	for(T=0,i=1;i<=N;i++)if(!m[i])++T,D(i);
	sort(v.begin(),v.end());
	for(i=0;i<v.size();i++)printf("%d %d %d\n",v[i].first,v[i].second.first,v[i].second.second);
}

C++: #include<bits/stdc++.h>
using namespace std;
int a[101][101],f[101],e[101],nt[101],cur,i,j,n,t=0;
int color[101];
void dfs(int u){
    f[u]=++t;
    color[u]=1;
    for(int v=0;v<n;++v){
        if(color[v]==0&&a[u][v]){
            dfs(v);
        }
    }
    e[u]=++t;
}
int main(){
    int u,v;
    scanf("%d",&n);
    for(i=0;i<n;++i){
        scanf("%d %d",&u,&cur);
        for(j=0;j<cur;++j){
            scanf("%d",&v);
            a[u-1][v-1]=1;
        }
    }
    for(i=0;i<n;++i){
        if(!color[i]){
            dfs(i);
        }
    }
    for(i=0;i<n;++i)    printf("%d %d %d\n",i+1,f[i],e[i]);
    return 0;
}

C++: #include <algorithm>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <time.h>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <numeric>
#include <limits>
#include <type_traits>

using namespace std;
#define SAY_YES cout << "YES" << endl;
#define SAY_Yes cout << "Yes" << endl;
#define SAY_NO cout << "NO" << endl;
#define SAY_No cout << "No" << endl;
#define IFYES(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "YES" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "NO" << endl;  \
    }
#define IFYes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "Yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "No" << endl;  \
    }
#define IFyes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "no" << endl;  \
    }
#define DEBUG_OUTPUT_ARRAY(XXX, ONE)                            \
    for (int i = 0; i < (ONE); i++)                             \
    {                                                           \
        cout << "DEBUG: i = " << i << " -> " << XXX[i] << endl; \
    }
#define DEBUG_OUTPUT_ARRAY2(XXX, ONE, TWO)                             \
    for (int i = 0; i < (ONE); i++)                                    \
    {                                                                  \
        cout << "<<< i = " << i << " >>>" << endl;                     \
        for (int j = 0; j < (TWO); j++)                                \
        {                                                              \
            cout << "DEBUG: j = " << j << " -> " << XXX[i][j] << endl; \
        }                                                              \
    }
#define DEBUG_OUTPUT_ARRAY2_BOX(XXX, ONE, TWO) \
    for (int i = 0; i < (ONE); i++)            \
    {                                          \
        cout << i << "  ";                     \
        for (int j = 0; j < (TWO); j++)        \
        {                                      \
            cout << XXX[i][j] << " ";          \
        }                                      \
        cout << endl;                          \
    }

typedef pair<long long int, long long int> pll;


const long long int mod = 1000000007;
const long long int INF = 1e18;
const long double PI=3.14159265358979323; 

long long int N,K,M,A[200],k[200203]={},v[2003],res[200][2],sum=0,cou=0,ten=1;
long long int dp[3005][3005]={};
string S,T;
vector<long long int>vec[200];

bool used[200]={};

long long int dfs(long long int now,long long int time){
    if(used[now]){return time;}
    used[now]=true;
    res[now][0]=time;
    long long int nex=time+1;
    for(long long int j = 0; j < vec[now].size(); j++){
        nex=dfs(vec[now][j],nex);
    }
    res[now][1]=nex;
    return nex+1;
}
int main()
{
    cout << fixed << setprecision(18);
    cin>>N;
    
    for(long long int i = 0; i < N; i++){
        cin>>A[i]>>k[i];
        A[i]--;
        for(long long int j = 0; j < k[i]; j++){
            cin>>v[j];
            v[j]--;
            vec[i].push_back(v[j]);
        }
    }
    long long int tim=1;
    for(long long int i = 0; i < N; i++){
        if(!used[i]){
            tim=dfs(i,tim);
        }
    }
    for(long long int i = 0; i < N; i++){
        cout<<i+1<<" "<<res[i][0]<<" "<<res[i][1]<<endl;
    }
    
}