Go: package main

import "fmt"

type node struct {
	id, d, v int
	adj      []node
}

var n int
var seen []bool
var graph []node

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func dfs(v, t int) int {
	// fmt.Printf("dfs(v %d, t %d) en:\n", v, t)
	seen[v] = true
	graph[v].v = t
	tt := t
	for _, vv := range graph[v].adj {
		if !seen[vv.id] {
			tt = max(tt, dfs(vv.id, tt+1))
		}
	}
	graph[v].d = tt + 1
	// fmt.Printf("dfs(v %d, t %d) ex: d %d\n", v, t, graph[v].d)
	return graph[v].d
}

func main() {
	fmt.Scan(&n)
	graph = make([]node, n+1)
	for i := 1; i <= n; i++ {
		var u, k, v int
		fmt.Scan(&u, &k)
		graph[u].id = u
		// 頂点uはk個の隣接頂点を持っている
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			var t node
			t.id = v
			graph[u].adj = append(graph[u].adj, t)
		}
	}
	// fmt.Println("n", n, "graph", graph)
	seen = make([]bool, n+1)
	// t := dfs(1, 1)
	v, t := 1, 1
	done := false
	for !done {
		tt := dfs(v, t)
		done = true
		for i := range seen {
			if !seen[i] {
				done = false
				v = graph[i].id
				t = tt
				break
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, graph[i].v, graph[i].d)
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <vector>

using namespace std;
const int maxn=100+10;
int n;
vector<int> g[maxn];
int s[maxn],e[maxn];
int vis[maxn];
int t=1;
void dfs(int u)
{
    vis[u]=1;
    s[u]=t++;
    for(int i=0;i<g[u].size();i++)
    {
        int v=g[u][i];
        if(!vis[v])
        {
            dfs(v);
        }
    }
    e[u]=t++;
}
int main()
{
//    freopen("in.txt","r",stdin);
    scanf("%d",&n);
    int no,cnt,dd;
    for(int i=0;i<n;i++)
    {
        scanf("%d%d",&no,&cnt);
        for(int j=0;j<cnt;j++)
        {
            scanf("%d",&dd);
            g[no-1].push_back(dd-1);
        }
    }
    memset(vis,0,sizeof(vis));
    for(int i=0;i<n;i++)
    {
        if(!vis[i])   dfs(i);
    }
    for(int i=0;i<n;i++)
    {
        printf("%d %d %d\n",i+1,s[i],e[i]);
    }
    return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <string>
#include <cstring>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iomanip>
#include <limits>
#include <map>
#include <queue>
#include <stack>
#include <vector>

#define FOR(i,k,n) for(int (i) = (k); (i) < (n); ++(i))
#define rep(i,n) FOR(i,0,n)
#define pb push_back
#define all(v) begin(v), end(v)
#define debug(x) cerr << #x << ": " << x << endl
#define debug2(x,y) cerr << #x << ": " << x << ", " << #y << ": " << y << endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
template<class T> using vv=vector<vector<T>>;
typedef deque<int> di;
typedef deque<deque<int>> ddi;

short d[101] = {}, v[101] = {};
bool  p[101][101] = {};
short t = 0;
int n;  

void dfs(int i) {
    d[i] = ++t;
    rep(j,n+1) {
        if(p[i][j] == 1 & d[j] == 0) {
            dfs(j);     
        }
    }
    v[i] = ++t;
}

int main() {
    cin >> n;
    rep(i,n) {
        short u,k;
        cin >> u >>k; 
        rep(j,k) {
            int tmp;
            cin >> tmp;
            p[u][tmp] = 1; 
        }
    }
    dfs(1);
    FOR(i,1,n+1) {
        cout << i << " " << d[i] << " " << v[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 color[N], nt[N], M[N][N], d[N], f[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 i = 0; i < n; i++) {
   	   if(color[i] == WHITE) {
   	   	   dfs_visit(i);
   	   }
   }
   
   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++) {
		cin >> u >> k;
		u--;
		for(int j = 0; j < k; j++) {
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	
    dfs();
    
    return 0;
	
}

C++: //
//  main.cpp
//  depth_first_search
//
//  Created by ???????????? on 2017/10/22.
//  Copyright ?? 2017 ????????????. All rights reserved.
//

#include <iostream>
#include <stdio.h>

#define n_max 100

using namespace std;

int n, t = 0;
int M[n_max][n_max], color[n_max], d[n_max], f[n_max];

void encode_graph(int n){
    int i, j, id, num, node;
    
    //initialize with 0
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            M[i][j] = 0;
        }
    }
    
    for (i = 0; i < n; i++){
        scanf("%d", &id);
        scanf("%d", &num);
        for(j = 0; j < num; j++){
            scanf("%d", &node);
            M[id-1][node-1] = 1;
        }
    }
}

void dfs(int u){
    color[u] = 1;
    d[u] = ++t;
    for (int v = 0; v < n; v++){
        if((M[u][v]) && (color[v] == 0)){
            dfs(v);
        }
    }
    color[u] = 2;
    f[u] = ++t;
}

void dfs_init(int n){
    for(int i = 0; i < n ; i++){
        color[i] = 0;
    }
    dfs(0);
}


int main(int argc, const char * argv[]) {
    scanf("%d", &n);
    
    encode_graph(n);
    
    dfs_init(n);
    
    for(int i = 0; i < n; i++){
        cout<<i+1<<" "<<d[i]<<" "<< f[i]<<endl;
    }
    
//    std::cout << "Hello, World!\n";
    return 0;
}

C++: #include <iostream>
#include <stdio.h>

using namespace std;
int d[100] = {}, f[100] = {}, ans[100][100] = {};
int now = 1, n;
int dfs(int i) {
	d[i] = now;
	++now;
	for (int u = 0; u < n; ++u) {
		if (ans[i][u] == 1 && d[u] == 0) {
			dfs(u);
		}
	}
	f[i] = now;
	++now;
	return 0;
}
int main() {
	int u, k, tmp, now=0;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> u >> k;
		for (int j = 0; j < k; j++)
		{
			cin >> tmp;
			ans[u - 1][tmp - 1] = 1;
		}
	}
	/*
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n;++j) {
			cout << ans[i][j] << " ";
		}
		cout << endl;
	}
	*/
	for (int i = 0; i < n; ++i) {
		if (d[i] == 0) {
			dfs(i);
		}
	}
	for (int i = 0; i < n; i++)
	{
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}