Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

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 M[N][N], color[N], d[N], f[N], nt[N];
int tt,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] = BLACK;
	d[r] = ++tt;
	
	while(!S.empty()) {
		int u = S.top();
		int v = next(u);
		if(v != -1) {
			   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 j = 0; j < n; j++) {
		if(color[j] == WHITE) {
			dfs_visit(j);
		}
	}
	
	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 i = 0; i < k; i++ ) {
	       cin >> v;
	       v--;
	       M[u][v] = 1;	
	    }		
	}
	
	
	dfs();
	
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <map>
#include <unordered_map>
#include <cstring>

using namespace std;
using ll = long long;
using pint = pair<int, int>;
using Graph = vector<vector<int>>;

ll INF = 1LL << 60;

Graph G;
vector<bool> seen;
vector<int> d, f;

void dfs(Graph& G, int v, int& num) {
	seen[v] = true;
	d[v] = num++;
	for (int nv : G[v]) {
		if (seen[nv]) continue;
		dfs(G, nv, num);
	}
	f[v] = num++;
}

int main() {
	int n;
	cin >> n;
	G.resize(n);
	seen.resize(n);
	d.resize(n);
	f.resize(n);
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		u--;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			v--;
			G[u].push_back(v);
		}
	}

	int num = 1;
	for (int i = 0; i < n; i++) {
		if (!seen[i]) dfs(G, i, num);
	}
	for (int i = 0; i < n; i++) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
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, 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[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 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 ++) {
    cin >> u >> k;
    u --;
    for (int j = 0; j < k; j ++) {
      cin >> v;
      v --;
      M[u][v] = 1;
    }
  }

  dfs();

  return 0;
}

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

using namespace std;
using Graph=vector<vector<int>>;

void depth_firstsearch(const Graph& graph, int vertex, vector<bool>& seen, vector<int>& first_order, vector<int>& last_order, int& time) {

	first_order.at(vertex) = time++;
	seen.at(vertex) = true;

	for (int v : graph.at(vertex)) {
		if (seen.at(v)) continue;
		depth_firstsearch(graph, v, seen, first_order, last_order, time);
	}
	last_order.at(vertex) = time++;
}

int main(void) {
	int size, vnum, adjnum, temp, time;
	cin >> size;
	Graph graph(size);
	vector<bool> seen(size, false);
	vector<int> first_order(size);
	vector<int> last_order(size);

	for (int i = 0; i < size; i++) {
		cin >> vnum >> adjnum;
		for (int j = 0; j < adjnum; j++) {
			cin >> temp;
			graph.at(vnum - 1).push_back(temp - 1);
		}
	}
	time = 1;
	for (int i = 0; i < size; i++) {
		if(seen.at(i)==false) depth_firstsearch(graph, i, seen, first_order, last_order, time);
	}

	for (int i = 0; i < size; i++) {
		cout << i + 1 << " " << first_order.at(i) << " " << last_order.at(i) << endl;
	}
	return 0;
}