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<algorithm>
#include<string>
#include<vector>
#include<stack>
using namespace std;

static const int N = 100;
static const int WHITE = 0; //訪問した
static const int GRAY = 1; //訪問中
static const int BLACK = 2; //全て訪問済み

int n, M[N][N]; //頂点の個数、辺のリスト
int color[N], d[N], f[N], tt; //色、発見時刻、完了時刻、時間
int nt[N];

int next(int u) {
	for (int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if (M[u][v]) return v;
	}
	return -1;
}

void dfs_visit(int r) {
	for (int i = 0; i < n; i++) nt[i] = 0;

	stack<int> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++tt;

	while (!S.empty()) {
		int u = S.top();
		int v = next(u);
		if (v != -1) {
			if (color[v] == WHITE) {
				color[v] = GRAY;
				d[v] = ++tt;
				S.push(v);
			}
		}
		else {
			S.pop();
			color[u] = BLACK;
			f[u] = ++tt;
		}
	}
}

void dfs() {
	for (int i = 0; i < n; i++) {
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 0;
	for (int u = 0; u < n; u++) {
		if (color[u] == WHITE) dfs_visit(u);
	}
	for (int i = 0; i < n; i++) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
}

int main(void) {
	int u, k, v; //頂点番号、出次数、隣接リスト
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}
	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();
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF 922337203685477580
typedef long long ll;

int matrix[110][110];
int d[110];
int f[110];
int n;
int elapsed = 1;

void visit(int v) {
  d[v] = elapsed++;

  FOR(i, 1, n + 1) {
    if (matrix[v][i] && d[i] < 0 ) {
      visit(i);
    }
  }
  f[v] = elapsed++;
}

int main() {
  REP(x, 110) {
    REP(y, 110) {
      matrix[x][y] = 0;
    }
    d[x] = -1;
    f[x] = -1;
  }

  // int n;
  cin >> n;

  REP(_, n) {
    int v, num;
    cin >> v >> num;

    REP(i, num) {
      int cv;
      cin >> cv;
      matrix[v][cv] = 1;
      // matrix[cv][v] = 1;
    }
  }


  visit(1);

  FOR(v, 1, n + 1) {
    cout << v << " " << d[v] << " " << f[v] << endl;
  }


  return 0;
}

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;





//用栈实现深度优先搜索


/**
 * color 标记访问状态的数组，
 * M[N][N] 邻接矩阵 如果存在定点i到顶点j的边，则M[i][j]=trul
 * Stack 栈，暂存访问过程中的顶点
**/
int n,M[N][N];
int color[N],d[N],f[N],tt;
int nt[N];


//按序号，获取和u相邻的v
int next(int u){
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;
        if(M[u][v]) return v;
    }
    return -1;
}

//用栈实现深度优先搜索
void dfs(int r){
    for(int i=0;i<n;i++) nt[i]=0;

    stack<int> S;
    S.push(r);
    color[r]=GRAY;
    d[r]=++tt;

    while(!S.empty()){
        int u=S.top();
        int v=next(u);

        if(v!=-1){
            if(color[v]==WHITE){
                color[v]=GRAY;
                d[v]=++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u]=BLACK;
            f[u]=++tt;
        }
    }

}

void dfs(){
    //初始化
    for(int i=0;i<n;i++){
        color[i]=WHITE;
        nt[i]=0;
    }
    tt=0;

    for(int u=0;u<n;u++){
        if(color[u]==WHITE)
            dfs(u);
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    return;
}
int main(){
    int u,k,v;
    cin>>n;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            M[i][j]=0;
        }
    }
    for(int i=0;i<n;i++){
        cin>>u>>k;

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

    dfs();
    return 0;
}

C++: #include<iostream>
#include<stack>
using namespace std;
#define N 101
#define gray 1
#define white 0
#define black 2
int n,m[N][N];
int color[N],d[N],f[N],tt;
int nt[N];
int next(int u)
{
	for(int v=nt[u];v<n;v++)
	{
		nt[u]=v+1;
		if(m[u][v]) return v;
	}
	return -1;
}
void dfs_v(int u)
{
	for(int i=1;i<=n;i++)
	{
		nt[i]=0;
	}
	stack<int> s;
	s.push(u);
	d[u]=++tt;
	color[u]=gray;
	while(!s.empty())
	{
		int x=s.top();
		int v=next(x);
		if(v!=-1)
		{
			if(color[v]==white)
			{
				color[v]=gray;
				d[v]=++tt;
				s.push(v);
			}
		}else
			{
				s.pop();
				color[x]=black;
				f[x]=++tt;
			}
	}
}
void dfs()
{
	for(int i=1;i<=n;i++)
	{
		color[i]=white;
		nt[i]=0;
	}
	tt=0;
	for(int i=1;i<=n;i++)
	{
		if(color[i]==white)
		{
			dfs_v(i);
		}
	}
	for(int i=1;i<=n;i++)
	{
		printf("%d %d %d\n",i,d[i],f[i]);
	}
}
int main()
{
	int v,k,u;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			m[i][j]=0;
		}
	}
	for(int i=1;i<=n;i++)
	{
		cin>>u>>k;
		for(int j=1;j<=k;j++)
		{
			cin>>v;
			m[u][v]=1;
		}
	}
	dfs();
	return 0;
}

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

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int M[N][N] = {0}, color[N] = {0}, d[N], f[N], tt = 0, n;

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

int main(void) {
  int u, v, k, i, j;

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

  for (u = 0; u < n; u++) {
    cout << u + 1 << " " << d[u] << " " << f[u] << endl;
  }

  return 0;
}