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 <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ll long long 

int n,t;
vector<int>G[101];
int d[101],f[101];
bool used[101];

void dfs(int v){
  used[v]=true;
  d[v]=++t;
  rep(i,G[v].size()){
    int e=G[v][i];
    if(used[e]==false)dfs(e);
  }
  f[v]=++t;
}

int main(){
  cin>>n;
  rep(i,n){
    int u,k;
    cin>>u>>k;
    u--;
    rep(j,k){
      int v;
      cin>>v;
      v--;
      G[u].push_back(v);
    }
  }
  rep(i,n)if(used[i]==false)dfs(i);
  rep(i,n)cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
  return 0;
}

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

int n, t = 0, d[110] = {}, f[110];
bool a[110][110] = {};

void dfs(int u){
  d[u] = ++t;
  
  for(int i = 1;i <= n;i++) if(a[u][i] && d[i] == 0) dfs(i);
  
  f[u] = ++t;
}

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

C++: #include<stdio.h>
#define N 100
#define WHITE 0  //未访问节点
#define GRAY 1
#define BLACK 2

int n,M[N][N];
int color[N],d[N],f[N],tt;

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;
} 

void dfs()
{
	int u;
	for(u=0;u<n;u++)
	{
		color[u]=WHITE;
	}
	tt=0;
	for(u=0;u<n;u++)
	{
		if(color[u]==WHITE)
			dfs_visit(u);
	}
	for(u=0;u<n;u++)
	{
		printf("%d %d %d\n",u+1,d[u],f[u]);
	}
}
int main()
{
	int u,v,k,i,j;
	scanf("%d",&n);
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
			M[i][j]=0;
	}
	for(i=0;i<n;i++)
	{
		scanf("%d %d",&u,&k);
		u--;
		for(j=0;j<k;j++)
		{
			scanf("%d",&v);
			v--;
			M[u][v]=1;
		}
	}
	dfs();
	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 BRACK = 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_visit(int r) {
	for (int i = 0; i < n; i++) {//nt????????????
		nt[i] = 0;
	}

	stack<int> S;//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] = BRACK;
			f[u] = ++tt;
		}
	}
}

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

	//????¨???????u????§??????¨????????±???????????¢?´¢
	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() {
	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++) {//??????M????????????????´?
		cin >> u >> k;
		u--;//0?????????????????????
		for (int j = 0; j < k; j++) {
			cin >> v;
			v--;//0?????????????????????
			M[u][v] = 1;
		}
	}

	dfs();

	return 0;
}

C++: #include<iomanip>
#include<limits>
#include<thread>
#include<utility>
#include<iostream>
#include<string>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<stack>
#include<queue>
#include<cmath>
#include<numeric>
#include<cassert>
#include<random>
#include<chrono>
#include<unordered_map>
#include<fstream>
#include<list>
#include<typeinfo>
#include<functional>
using namespace std;
typedef unsigned long long int ull;
typedef long long int ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pi;
typedef pair<double,double> pd;
typedef pair<double,ll> pdl;
#define F first
#define S second
const ll E=1e18+7;
const ll MOD=1000000007;

vector<vector<ll>> edge;
vector<ll> dp;
vector<ll> fi;

ll Time=0;

void dfs(ll where){
    Time++;
    dp[where]=Time;
    for(int i=0;i<edge[where].size();i++){
        const ll &to=edge[where][i];
        if(dp[to]!=-1){continue;}
        dfs(to);
    }
    Time++;
    fi[where]=Time;
}

int main(){
    ll n;
    cin>>n;
    edge.resize(n);
    dp.resize(n,-1);
    fi.resize(n,-1);
    for(int i=0;i<n;i++){
        ll u,k;
        cin>>u>>k;
        u--;
        for(int t=0;t<k;t++){
            ll v;
            cin>>v;
            v--;
            edge[u].push_back(v);
        }
    }
    for(int i=0;i<n;i++){
        if(dp[i]==-1){dfs(i);}
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<dp[i]<<" "<<fi[i]<<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;

int n, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

int next(int u){
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if(M[u][v] = 1) 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 {
		   color[v] = BLACK;
		   S.pop();
		   f[v] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}	
	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() {
	int n, k , u, v;
	tt = 0;
	cin >> n;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}
	cin >> k >> u;
	u--;
	for(int i = 0; i < k; i++) {
	    cin >> v;
	    v--;
		M[u][v] = 1; 
	}
	dfs();
	return 0;
}