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<vector>
#include<utility>
using namespace std;
vector<int> l[101];
int matrix[100][100];
pair<int,int> t[101];
bool visited[101];
int tim=0;
void dfs(int cur)
{
    tim+=1;
    t[cur].first=tim;
    //cerr<<"visiting "<<cur<<' '<<tim<<endl;
    visited[cur]=true;
    
    for(int i=0;i<l[cur].size();i++)
    {
        if((matrix[cur-1][l[cur][i]-1]==1)&&(visited[i]==false))
        {
            dfs(l[cur][i]);
        }
    }
    
    tim+=1;
    t[cur].second=tim;
    
    
}
int main()
{
    int n;
    cin>>n;
    for(int i=0;i<n;i++)
    {
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            int tmp;
            cin>>tmp;
            l[u].push_back(tmp);
        }
    }
    
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            matrix[i][j]=0;
        }
    }
    for(int i=1;i<n+1;i++)
    {
        visited[i]=false;
        for(int j=0;j<l[i].size();j++)
        {
            matrix[i-1][l[i][j]-1]=1;
        }
    }
    
    for(int i=1;i<n+1;i++)
    {
        if(visited[i]==false)
            dfs(i);
    }
    
    for(int i=1;i<n+1;i++)
    {
        cout<<i<<" "<<t[i].first<<" "<<t[i].second<<endl;
    }
}

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

using namespace std;

int color[100];
int d[100];
int f[100];
int G[100][100];
int nt[100];
int n;

int WHITE = 1;
int GRAY = 2;
int BLACK = 3;

int _time = 0;

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

  return -1;
}

void dfs(int r) {
  for (int i = 0; i < n; i++) nt[i] = 0;

  stack<int> S;

  S.push(r);
  color[r] = GRAY;
  d[r] = ++_time;

  while(!S.empty()){
    int u = S.top();
    int v = next(u);

    if(v != -1) {
      if(color[v] == WHITE) {
        color[v] = GRAY;
        d[v] = ++_time;

        S.push(v);
      }
    } else {
      S.pop();
      color[u] = BLACK;
      f[u] = ++_time;
    }
  }
}

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

  for(int u = 0; u < n; u++) {
    if (color[u] == WHITE) {
      dfs(u);
    }
  }
}

int main() {
  int m, k, l;
  cin >> n;

  for (int i = 0; i < n; i++) {
    cin >> k;
    cin >> m;

    for (int j = 0; j < m; j++) {
      int l;
      cin >> l;

      G[k-1][l-1] = 1;
    }
  }

  for (int i = 0; i < n; i++) {
    dfs_init();
  }

  for (int i = 0; i < n; i++) {
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
}