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<stdio.h>
#include<algorithm>
#include<stack>
#include<string.h>
using namespace std;
#define NIL -2000000001
#define MAX 101
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n = 0;
int adl[MAX][MAX], deg[MAX];
int adm[MAX][MAX];
int color[MAX];
int d[MAX][2];
stack<int> depth;


void dfs() {
  int time = 1;
  for ( int i = 0; i < n; i++ ) {
    color[i] = WHITE;
  }
  depth.push(0);
  color[0] = GRAY;
  d[0][0] = time++;

  while (!depth.empty()) {
    int top = depth.top();

    int next = NIL;
    for (int i = 0; i < n; i++) {
      if (adm[top][i] == 1 && color[i] == WHITE) {
        next = i;
        depth.push(i);
        color[i] = GRAY;
        d[i][0] = time++;
        break;
      }
    }

    if (next == NIL) {
      color[top] = BLACK;
      d[top][1] = time++;
      depth.pop();
    }
    // WHITEになっている島を探す
    if (depth.empty()) {
      for (int i = 0; i < n; i++) {
        if (color[i] == WHITE) {
          depth.push(i);
          color[i] = GRAY;
          d[i][0] = time++;
          break;
        }
      }
    }

  }
}

int main() {
  scanf("%d", &n);
  for ( int i = 0; i < n; i++ ) {
    for ( int j = 0; j < n; j++ ) {
      adm[i][j] = 0;
    }
  }
  for ( int i = 0; i < n; i++ ) {
    int num;
    scanf("%d", &num);
    num--;
    scanf("%d", &deg[num]);
    for ( int j = 0; j < deg[num]; j++) {
      scanf("%d", &adl[num][j]);
      adl[num][j]--;
      adm[num][adl[num][j]] = 1;
    }
  }

  dfs();

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



  return 0;
}

C++: #include <bits/stdc++.h>
#define REP0(i,n) for(int i=0;i<n;i++)
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;
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){
  REP0(i,n) 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(){
  REP0(i,n){
    color[i]=WHITE;
    nt[i]=0;
  }
  tt=0;
  REP0(u,n) if(color[u]==WHITE) DFS_visit(u);
  REP0(i,n) printf("%d %d %d\n",i+1,D[i],F[i]);
}
int main(){
  int u,k,v,j;
  scanf("%d",&n);
  REP0(i,n){
    REP0(j,n) M[i][j]=0;
  }
  REP0(i,n){
    scanf("%d %d",&u,&k);
    REP0(j,k){
      scanf("%d",&v);
      M[--u][--v]=1;
    }
  }
  DFS();
  return 0;
}

C++: #include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>
using namespace std;

#define MAXN 100
int n, timecount = 1;
int ans[MAXN][MAXN];
int d[MAXN], f[MAXN]; // d[i]はdを最初に発見した時刻,f[i]は調べ終わった時刻
bool is_reach[MAXN];

int dfs(int p);

int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        d[i] = -1;
        f[i] = -1;
        is_reach[i] = false;
    }
    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
            ans[i][j] = 0;
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int tmp;
            cin >> tmp;
            ans[u-1][tmp-1] = 1;
        }
    }
//    for (int i = 0; i < n; i++) {
//        for (int j = 0; j < n; j++) {
//            if (j == n-1) cout << ans[i][j];
//            else cout << ans[i][j] << " ";
//        }
//        cout << endl;
//    }
    int start = 0;
    while (1) {
        dfs(start);
        int i;
//        printf("%d search end\n", start);
        for (i = 0; i < n; i++) {
            if (f[i] == -1) {
                start = i;
                break;
            }
        }
        if (i == n) break;
//        printf("next: %d\n", start);
    }
    for (int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
    return 0;
}

int dfs(int p)
{
    int ret = 0, count = 1;
    is_reach[p] = true;
    if (d[p] == -1) d[p] = timecount++;
    for (int i = 0; i < n; i++) {
        if (ans[p][i] == 1 && is_reach[i] == false && p != i) {
            dfs(i);
        }
    }
    if (f[p] == -1) f[p] = timecount;
    timecount++;
    return 0;
}

C++: /*
　　こんにちは。あたしはｶｳｶﾞｰﾙ。
　　redcoderになるためAtCoderを巡る旅をしてます。

　　　 　 ＿_
　　　 ヽ|＿_|ノ　　　　ﾓｫ
　　　　||‘‐‘||ﾚ　　_)_, ―‐ 、
　　　　/(Ｙ (ヽ＿ /・ ヽ　　 ￣ヽ
　　　　∠ ＿ ゝ　 ｀^ヽ ﾉ.::::_(ノヽ
　　　　 _/ヽ　 　　  /ヽ￣￣/ヽ
*/

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define dump(x) cout << #x << " = " << (x) << endl
#define YES(n) cout << ((n) ? "YES" : "NO") << endl
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl
#define POSSIBLE(n) cout << ((n) ? "POSSIBLE" : "IMPOSSIBLE") << endl
#define Possible(n) cout << ((n) ? "Possible" : "Impossible") << endl

#define rep(i, n) REP(i, 0, n)                  // 0, 1, ..., n-1
#define REP(i, x, n) for(int i = x; i < n; i++) // x, x + 1, ..., n-1
#define FOREACH(x, a) for(auto &(x) : (a))

#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()

#define COUT(x) cout << (x) << endl

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

using Graph = vector<vector<int>>;
vector<bool> seen;
vector<int> first_order;
vector<int> second_order;

void dfs(const Graph &G, int v, int &ptr) {
    first_order[v] = ptr++;
    seen[v]        = true;

    for(const auto &next_v : G[v]) {
        if(seen[next_v]) continue;
        dfs(G, next_v, ptr);
    }

    second_order[v] = ptr++;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    Graph G(n + 1); // 1-indexed
    rep(i, n) {
        int v, k;
        cin >> v >> k;
        rep(i, k) {
            int to_v;
            cin >> to_v;
            G[v].push_back(to_v);
        }
    }
    // 頂点1スタート
    seen.assign(n + 1, false);
    first_order.resize(n + 1);
    second_order.resize(n + 1);
    int ptr = 1;
    REP(i, 1, n + 1) {
        if(!seen[i]) dfs(G, i, ptr);
    }

    REP(i, 1, n + 1) {
        cout << i << " " << first_order[i] << " " << second_order[i] << endl;
    }
}