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 debug(x) cout <<"DEBUG"<<" "<< #x << ":" << x << '\n'

// n回繰り返し
#define rep(i,n) for(int i = 0; i < ((int)(n)); i++)   // 0-indexed昇順
#define rep1(i,n) for(int i = 1; i <= ((int)(n)); i++) // 1-indexed昇順
#define rrep(i,n) for(int i = ((int)(n)-1); i >= 0; i--)  // 0-indexed降順
#define rrep1(i,n) for(int i = ((int)(n)); i >= 1; i--)   // 1-indexed降順
#define all(x) (x).begin(),(x).end()

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<vi> vii;  // 2次元配列
typedef vector<ll> vll;
typedef vector<double> vd;
typedef pair<int, int> PII;

template<typename T>
using vec = vector<T>;
template<class T>
using maxheap = std::priority_queue<T>;
template<class T>
using minheap = std::priority_queue<T, std::vector<T>, std::greater<T>>;

template<class T,class U> inline bool chmax(T &a, const U &b){if(a<b){a=b;return 1;}return 0;}
template<class T,class U> inline bool chmin(T &a, const U &b){if(a>b){a=b;return 1;}return 0;}

const ld Pi = std::acos(-1.0L);
const ll infll = (1LL<<62)-1;
const int inf = (1<<30)-1;
const int mod = 1000000007;
// const int mod = 998244353;

/*GRAPH_TEMPLATE=============================================*/
template<typename T>
class Edge {
public:
    int srch; //searched?探索状態記録「null = -1」
    int to; //辺の行き先
    T cost; //辺の重み
    Edge(int t, T w) : srch(-1), to(t), cost(w) {}
    Edge(int t, T w, int src) : srch(src), to(t), cost(w) {}
};
template<typename T>
using W_Graph = std::vector<std::vector<Edge<T>>>;   //重み付きグラフ
using Graph = std::vector<std::vector<int>>;         //通常グラフ
template<typename T>
using Matrix = std::vector<std::vector<T>>;          //隣接行列(使わなさそう...)


vi d,f;
Graph g;
int TIME;
/*FUNCs=================================================*/
void recursive(int u) {
    d[u] = ++TIME;
    for(auto &v : g[u]) {
        if(d[v] != 0) continue;
        recursive(v);
    }
    f[u] = ++TIME;
}

/*MAIN==================================================*/
signed main(){
    int _StartTime_ = clock();
    cin.tie(nullptr);
    ios::sync_with_stdio(false);   //cin cout 高速化
    // cout << fixed << setprecision(15);

    int n; cin >> n;
    d.resize(n+1), f.resize(n+1);
    g.resize(n+1);

    rep(i,n) {
        int u,v; cin >> u;
        u;
        g[0].push_back(u);
        int k; cin >> k;
        rep(j,k) {
            cin >> v;
            v;
            g[u].push_back(v);
        }
    }

    TIME = -1;
    recursive(0);

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

    // printf("ExcutionTime: %d /ms\n",1000*(int)((clock()-_StartTime_)/CLOCKS_PER_SEC));
}

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

static const int DFS_VISIT_NO   = 0;
static const int DFS_VISIT_NOW  = 1;
static const int DFS_VISIT_DONE = 2;

static int g_time = 0;
static int g_setime[100][2] = {0};

void DfsVisit(int graph[][100], int num, int node, vector<int> &state)
{
    int i;

    ++g_time;
    g_setime[node][0] = g_time;

    state[node] = DFS_VISIT_NOW;

    for (i = 0; i < num; i++) {
        if ((graph[node][i] == 1) && (state[i] != DFS_VISIT_DONE)) {
            DfsVisit(graph, num, i, state);
        }
    }

    state[node] = DFS_VISIT_DONE;

    ++g_time;
    g_setime[node][1] = g_time;

    return;
}


void DFS(int graph[][100], int num)
{
    int i;
    vector<int> state;

    for (i = 0; i < num; i++) {
        state[i] = DFS_VISIT_NO;
    }

    for (i = 0; i < num; i++) {
        if (state[i] == DFS_VISIT_NO) {
            DfsVisit(graph, num, i, state);
        }
    }

    for (i = 0; i < num; i++) {
        printf("%d %d %d\n", i+1, g_setime[i][0], g_setime[i][1]);
    }

    return;
}

int main(void)
{
    int i, j;
    int target, tnum, node;
    int num;
    int graph[100][100] = {0};

    scanf("%d", &num);

    for (i = 0; i < num; i++) {
        scanf("%d" "%d", &target, &tnum);
        --target;
        for (j = 0; j < tnum; j++) {
            scanf("%d", &node);
            --node;
            graph[target][node] = 1;
        }
    }

    DFS(graph, num);
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
#define WHITE 0
#define GRAY 1
#define BLACK 2
typedef long long LL;
const int MAXN = 110;
int n, mapp[MAXN][MAXN], color[MAXN], d[MAXN], f[MAXN], tt;

void dfs_visit(int u) {
	color[u] = GRAY;//参照したことを示す
	d[u] = ++tt; //発見した時間を示す　0からなので足してから
	for(int i = 0; i < n; i++) {
		if(mapp[u][i] == 1 && color[i] == WHITE) {//u,i間に辺があること,iが未探訪を確認
			dfs_visit(i);
		}
	}
	color[u] = BLACK;//uに関して終わったことを示す
	f[u] = ++tt; //終了した時間を示す　足してから

}

void dfs() {
	tt = 0;
	memset(color, 0, sizeof(color));//探訪情報をリセット
	for(int i = 0; i < n; i++) {
		if(color[i] == WHITE) {//未探訪なら探索
			dfs_visit(i);
		}
	}
	for(int i = 0; i < n; i++) {
		printf("%d %d %d\n", i+1, d[i], f[i]);
	}
}

int main() {
	int u, v, k;
	cin >> n;
	memset(mapp, 0, sizeof(mapp));//木情報をリセット
	for(int i = 0; i < n; i++) {
		cin >> u >> k;
		u--; //0から考えているのでノードの番号を1減らす
		while(k--) {
			cin >> v;
			v--;
			mapp[u][v] = 1;//uとvに辺があることを示す
		}
	}
	dfs();
	return 0;
}