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 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 <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); ++i)
using namespace std;

int G[100][100];
int d[100] = {0};
int f[100];
int now_time = 1;
stack<int> search_stack;

int main() {
    // 制約見て！！！デカかったらlong longにすること！
    int n, u, k, v;
    cin >> n;
    rep(i, n) {
        cin >> u >> k;
        u--;
        rep(j, k) {
            cin >> v;
            v--;
            G[u][v] = 1;
        }
    }
    rep(i,n){
        if(d[i]==0){
            search_stack.push(i);
            d[i]=now_time++;
        }
        while(search_stack.size() > 0) {
            int s = search_stack.top();
            rep(i, n + 1) {
                if(i == n) {
                    f[s] = now_time++;
                    search_stack.pop();
                }
                else if(s != i && d[i] == 0 && G[s][i] == 1) {
                    search_stack.push(i);
                    d[i] = now_time++; 
                    break;
                }
            }
        }
    }
    rep(i, n) { printf("%d %d %d\n", i + 1, d[i], f[i]); }
}

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

const int MAX_N = 100;

struct Node {
  int v;
  int firstVisitedTime;
  int lastVisitedTime;
  bool visited;
};

void visit(int *count, int n, std::vector<std::list<int> *> *graph, std::vector<struct Node *> *nodes) {
  (*count)++;
  
  struct Node *node = nodes->at(n);

  if (!node->visited) {
    node->firstVisitedTime = *count;
    node->visited = true;
  }  

  //  std::cout << (*count) << " = " << n << std::endl;

  std::list<int> *neighbors = graph->at(n);

  while (!neighbors->empty()) {
    int v = neighbors->front();
    neighbors->pop_front();
    
    if (!nodes->at(v)->visited) {
      visit(count, v, graph, nodes);
    }
  }

  (*count)++;
  node->lastVisitedTime = (*count);

  //  std::cout << (*count) << " = " << n << std::endl;
}

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

  int n = 0;
  std::cin >> n;

  std::vector<std::list<int> *> *graph = new std::vector<std::list<int> *>(n + 1);
  std::vector<struct Node *> *nodes = new std::vector<struct Node *>(n + 1);
  
  for (int i = 1; i <= n; i++) {
    int v = 0;
    std::cin >> v;

    int k = 0;
    std::cin >> k;

    std::list<int> *neighbors = new std::list<int>();

    for (int i = 0; i < k; i++) {
      int a = 0;
      std::cin >> a;

      neighbors->push_back(a);
    }

    graph->at(i) = neighbors;

    struct Node *node = (struct Node *) std::malloc(sizeof(struct Node));

    node->v = i;
    node->firstVisitedTime = 0;
    node->lastVisitedTime = 0;
    node->visited = false;
    
    nodes->at(i) = node;
  }

  int count = 0;
  int start = 1;

  visit(&count, start, graph, nodes);  

  for (std::vector<struct Node *>::iterator iterator = nodes->begin() + 1; iterator != nodes->end(); ++iterator) {
    struct Node *node = *iterator;
        
    std::cout << node->v << " " << node->firstVisitedTime << " " << node->lastVisitedTime << std::endl;
  }
  
  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define ALL(vec) vec.begin(), vec.end()
#define rALL(vec) vec.rbegin(), vec.rend()
using namespace std;
using ll = long long;

vector<int> d, f, color;
vector<vector<int>> A;
int cnt = 0;

int next(int i) {
    for (auto j : A[i]) {
        if (color[j] == 0) {
            d[j] = cnt;
            color[j] = 1;
            return j;
        }
    }
    f[i] = cnt;
    color[i] = 2;
    return -1;
}

void dfs(int u) {
    cnt += 1;
    stack<int> S;
    S.push(u);
    d[u] = cnt;
    color[u] = 1;
    while (!S.empty()) {
        cnt += 1;
        int i = S.top();
        int j = next(i);
        if (j != -1) S.push(j);
        else S.pop();
    }
}

int main() {
    int n;
    cin >> n;
    A = vector<vector<int>>(n, vector<int>(0));
    d = vector<int>(n, 0);
    f = vector<int>(n, 0);
    color = vector<int>(n, 0);
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(j, k) {
            int tmp;
            cin >> tmp;
            A[i].push_back(--tmp);
        }
    }
    rep(i, n) {
        if (color[i] == 0) dfs(i);
    }
    rep(i, n) {
        printf("%d %d %d\n", i + 1, d[i], f[i]);
    }
    return 0;
}