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 <stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, time1=0, M[N][N], color[N];
int nt[N], begin[N], end[N];

int next(int r)
{
	int i;
	for(i=nt[r]; i<n; i++)
	{
		nt[r]=i+1;
		if(M[r][i]==0)
			continue;
		if(color[i]==WHITE)
			return i;
	}
	return -1;
	
}

void dfs_visit(int r)
{
	int i, j;
	stack<int> S;
	S.push(r);
	color[r]=GRAY;
	begin[r]=++time1;
	
	while(!S.empty())
	{
		int u=S.top();
		int v=next(u);
		if(v!=-1)
		{
			begin[v]=++time1;
			color[v]=GRAY;
			S.push(v);
		}
		else
		{
			S.pop();
			color[u]=BLACK;
			end[u]=++time1;
		}

	}
}

void dfs()
{
	int i, j;
	for(i=0; i<n; i++)
	{
		color[i]=WHITE;
		nt[i]=0;
	}

	for(i=0; i<n; i++)
	{
		if(color[i]==WHITE)
		{
			dfs_visit(i);
		}
	}
	for(i=0; i<n; i++)
	{
		cout<<i+1<<" "<<begin[i]<<" "<<end[i]<<endl;
	}
}

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

	dfs();
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>

using namespace std;

#define FIND 0
#define END 1

int  N;
bool Path[101][101] = {false};
int  TIME[101][2] = {0};
int time_tt;


void DFS(int i){
    if(!(TIME[i][FIND])) {
        time_tt++;
        TIME[i][FIND] = time_tt;
    }
    
    for (int p = 1; p <= N; p++) {
        if (Path[i][p]) DFS(p);
    }
    
    if(!(TIME[i][END])) {
        time_tt++;
        TIME[i][END] = time_tt;
    }
}

int main(){
    cin >> N;
    int bb;
    for (int i = 1; i <= N; i++) {
        int K;
        scanf("%d %d",&bb,&K);
        for (int k = 0; k < K; k++) {
            int p;
            scanf("%d",&p);
            
            Path[i][p] = true;
        }
    }
    
    time_tt = 0;
    
    DFS(1);
    
    for (int i = 1; i <= N; i++) {
        printf("%d %d %d\n",i,TIME[i][FIND],TIME[i][END]);
    }
    
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define REP(i,m,n) for(int i=(m); i<(int)(n); i++)
#define RREP(i,m,n) for(int i=(int)(n-1); i>=m; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define aut(r,v) __typeof(v) r = (v)
#define each(it,o) for(aut(it,(o).begin()); it!=(o).end(); ++it)
#define reach(it,o) for(aut(it,(o).rbegin()); it!=(o).rend(); ++it)
#define fi first
#define se second
#define debug(...) {cerr<<"[L"<<__LINE__<<"] "; _debug(__VA_ARGS__);}

template<typename T1, typename T2> ostream& operator<<(ostream& o, const pair<T1, T2>& p)
{return o<<"("<<p.first<<", "<<p.second<<")";}
template<typename T>string join(const vector<T>&v, string del=", ")
{stringstream s;rep(i,v.size())s<<del<<v[i];return s.str().substr(del.size());}
template<typename T>ostream& operator<<(ostream& o, const vector<T>&v)
{if(v.size())o<<"["<<join(v)<<"]";return o;}
template<typename T>ostream& operator<<(ostream& o, const vector<vector<T> >&vv)
{int l=vv.size();if(l){o<<endl;rep(i,l){o<<(i==0?"[ ":",\n  ")<<vv[i]<<(i==l-1?" ]":"");}}return o;}
template<typename T>ostream& operator<<(ostream& o, const set<T>& st)
{vector<T> v(st.begin(),st.end());o<<"{ "<<join(v)<<" }";return o;}
template<typename T1, typename T2>ostream& operator<<(ostream& o, const map<T1, T2>& m)
{each(p,m){o<<(p==m.begin()?"{ ":",\n  ")<<*p<<(p==--m.end()?" }":"");}return o;}
inline void _debug(){cerr<<endl;}
template<class First, class... Rest>
void _debug(const First& first, const Rest&... rest){cerr<<first<<" ";_debug(rest...);}

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;

const double PI = (1*acos(0.0));
const double EPS = 1e-9;
const ll INF = 0x3f3f3f3f;
const ll INFL = 0x3f3f3f3f3f3f3f3fLL;
const ll mod = 1e9 + 7;

inline void finput(string filename) {
    freopen(filename.c_str(), "r", stdin);
}

vi g[110];
vi f, d;
int t = 1;

void dfs(int v, int p=-1){
    d[v] = t++;
    for(auto u : g[v]){
        if(u == p || d[u] != 0) continue;
        dfs(u, v);
    }
    f[v] = t++;
};

int main(){
    ios_base::sync_with_stdio(0);
    // finput("./input");
    int n; cin >> n;
    rep(i,n){
        int u,k; cin >> u >> k;
        rep(j,k){
            int v; cin >> v;
            g[u].push_back(v);
        }
    }

    f = vi(n+1), d = vi(n+1);
    REP(i,1,n+1){
        if(d[i] == 0) dfs(i);
    }
    REP(i,1,n+1){
        printf("%d %d %d\n", i, d[i], f[i]);
    }
    return 0;
}