Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

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

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

C++: #include <bits/stdc++.h>
using namespace std;
#define N 100
int t = 0;
stack<int> st;
int d[N + 1], f[N + 1], V[N + 1];
int adj[N + 1][N + 1];

void dfs(int i, int n)
{
    for (int j = 0; j < V[i]; j++)
    {
        if (d[adj[i][j]] == -1)
        {
            d[adj[i][j]] = ++t;
            dfs(adj[i][j], n);
        }
    }
    f[i] = ++t;
}

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

    for (int i = 0; i <= n; i++)
        d[i] = f[i] = -1;

    dfs(0, n);

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

C++: #include <iostream>
#include <stack>

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];

void input(){
    cin >> num;
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void dfs(){
    stack<int> S;
    S.push(0);
    dst[0] = 0;
    while(!S.empty()){
        int cur = S.top();
        S.pop();
        if(dst[cur]==-1 || dst[cur]== 0){
            for(int i=0;i<num;i++){
                if(matrix[cur][i]==1){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
        else{
            for(int i=0;i<num;i++){
                if(matrix[cur][i]==1){
                    if(dst[cur] +1 <= dst[i]){
                        S.push(i);
                        dst[i] = dst[cur] + 1;
                    }
                }
            }
        }
    }
    for(int i=0;i<num;i++){
        cout << i+1 << " " <<  dst[i] << endl;
    }
}

int main(){
    input();
    dfs();
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;
const int inf = 1e9;
const ll INF = 1e18;
const double pi = 3.14159265358979323846;
#define rep(i, n) for (int i = 0; i < n; i++)
using Graph = vector<vector<int>>;
using pint = pair<int, int>;
int dx[4] = { 1, 0, -1, 0 }, dy[4] = { 0, 1, 0, -1 };

int n;
vector<int> first, last;
bool seen[100] = {};

void dfs (const Graph& g, int u, int& ptr) {
    first[u] = ptr++;
    seen[u] = 1;
    for (auto next : g[u]) {
        if (seen[next]) continue;
        dfs (g, next, ptr);
    }
    last[u] = ptr++;
}

int main() {
    cin >> n;
    Graph g (n);
    first.resize (n);
    last.resize (n);
    rep (i, n) {
        int a, k;
        cin >> a >> k;
        rep (j, k) {
            int b;
            cin >> b;
            g[a - 1].push_back (b - 1);
            //g[b].push_back (a);
        }
    }
    int ptr = 0;
    rep (i, n) {
        if (first[i] == 0 && last[i] == 0) {
            dfs (g, i, ptr);
        }
    }

    rep (i, n) cout << i + 1 << " " << first[i] + 1 << " " << last[i] + 1 << "\n";
}

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

#define REP(i,n) for(int i=0;i<n;++i)

const int MAX_N = 100;
int n, t = 0, flag[MAX_N] = {0}, d[MAX_N], f[MAX_N], G[MAX_N][MAX_N] = {0};

void dfs(int u) {
  int v;
  flag[u] = 1;
  d[u] = ++t;
  REP(v, n) {
    if (!G[u][v]) continue;
    if (!flag[v]) dfs(v);
  }
  flag[u] = 2;
  f[u] = ++t;
}

int main() {
  int u, v, k;
  cin >> n;
  REP(i, n) {
    cin >> u >> k;
    REP(j, k) {
      cin >> v;
      G[u - 1][v - 1] = 1;
    }
  }
  REP(i, n) if (!flag[i]) dfs(i);
  REP(i, n) cout << i + 1 << ' ' << d[i] << ' ' << f[i] << endl;
  return 0;
}