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<bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for(int (i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int (i) = 1; (i) <= (n); (i++))
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#define yn {puts("Yes");}else {puts("No");}
#define printd(x) printf("%.12f\n", ans);
template<class T> bool chmin(T& a, const T& b) {if (a > b) {a = b; return 1;} return 0;}
template<class T> bool chmax(T& a, const T& b) {if (a < b) {a = b; return 1;} return 0;}
using namespace std;
using ll = long long;
using P = pair<int, int>;

vector<vector<int>> g(105);
vector<bool> visited(105);
vector<int> d(105, -1);
vector<int> f(105);

int nowTime = 0;

int dfs(int s) {
	visited[s] = true;
	nowTime++;
	if (d[s] == -1) d[s] = nowTime;

	for(auto v: g[s]) {
		if (visited[v]) continue;
		dfs(v);
	}
	
	bool ok = true;
	for (auto v: g[s]) {
		if (visited[v]) continue;
		ok = false;
	}
	if (ok) f[s] = nowTime + 1;
	return nowTime++;
}


int main(void) {
	int n;
	cin >> n;
	rep (i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		rep (j, k) {
			int v;
			cin >> v;
			v--;
			g[u].pb(v);
		}
	}

	rep (i, n) if (!visited[i]) dfs(i);

	rep (i, n) cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	return 0;
}

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

static const int N = 100;
int n,color[N],M[N][N],d[N],f[N];
int t;

void dfs_visit(int u){
  int v;
  color[u] = 1;
  d[u] = ++t;
  for (v = 0; v < n; v++) {
    if(M[u][v] == 0) continue;
    if(color[v] == 0) dfs_visit(v);
  }
  color[u] = 2;
  f[u] = ++t;
}
void dfs(){
  int u;

  for (u = 0; u < n; u++) {
    color[u] = 0;
  }
  t = 0;

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

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

int main() {
  int i,j,u,k,v;

  cin >> n;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }
  for (i = 0; i < n; i++) {
    cin >> u >> k;
    u--;
    for (j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }
  //cout << "done1" << endl;

  dfs();

  return 0;
}

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

int main() {
    int n;
    cin>>n;
    vector<vector<int> > arr(n);
    vector<int> tmparr;
    int u, k;
    int tmp;
    for(int i=0;i<n;++i){
        cin>>u>>k;
        u--;
        tmparr.clear();
        for(int j=0;j<k;++j){
            cin>>tmp;
            tmp--;
            tmparr.push_back(tmp);
        }
        arr[u] = tmparr;
    }
    stack<int> stack;
    stack.push(0);
    map<int, int> used;
    map<int, int> owari;
    map<int, pair<int, int> > ans;
    int state;
    int time = 1;
    while(!stack.empty()){
        while(!stack.empty()){
            state = stack.top();
            if(used[state]>0){
                if(owari[state]==0){
                    ans[state].second = time;
                    owari[state]++;
                    time++;
                }
                stack.pop();
            }
            else {
                ans[state].first = time;
                time++;
            }
            used[state]++;
            for(int i=arr[state].size()-1;i>=0;--i){
                if(used[arr[state][i]]==0){
                    stack.push(arr[state][i]);
                }
            }
        }
        for(int i=0;i<n;++i){
            if(used[i]==0){
                stack.push(i);
                break;
            }
        }
    }
    for(int i=0;i<n;++i){
        cout<<i+1<<" "<<ans[i].first<<" "<<ans[i].second<<endl;
    }
}

C++: #include <cstdio>

typedef struct vertex_{
    int found;
    int d;
    int f;
}vertex;

int search(vertex *array, int (*A)[101], int id, int n, int time){
    if(array[id].found)return time;
    array[id].found=1;
    array[id].d=++time;
    for(int i=1;i<=n;i++){
        if(A[id][i])time=search(array,A,i,n,time);
    }
    array[id].f=++time;
    return time;
}

int searchAll(vertex *array, int (*A)[101], int n){
    int time = 0;
    for(int id=1;id<=n;id++){
        if(!array[id].found){
            time=search(array,A,id,n,time);
            printf("%d\n",time);
        }
    }
    return time;
}

int main(){
    int i, j, n, u, k, v;
    scanf("%d",&n);
    vertex array[n+1];
    for(i=1;i<=n;i++)array[i].found=0;
    int A[101][101];
    for(i=1;i<=n;i++){
        for(j=1;j<=n;j++){
            A[i][j]=0;
        }
    }
    for(i=1;i<=n;i++){
        scanf("%d %d",&u,&k);
        for(j=0;j<k;j++){
            scanf("%d",&v);
            A[u][v]=1;
        }
    }
    int time = searchAll(array, A, n);
    for(i=1;i<=n;i++)printf("%d %d %d\n",i,array[i].d,array[i].f);
    return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <vector>
#include <math.h>
#include <set>
#include <map>
#include <string>
#include <stack>
#include <queue>
#include <iomanip>
#include <numeric>
#include <tuple>
#define _USE_MATH_DEFINES
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> plglg;
typedef tuple<int, int, int> tiii;
typedef tuple<ll, ll, ll> tlglglg;
double pi = 3.141592653589793;
ll mod = 1000000007;
int intmax = 2147483647;
int intmin = -2147483648;
ll llmax = 9223372036854775807;
ll llmin = -9223372036854775807;

struct edge {
    int to, cost;
};

int V;
vector<int> G[1000000];
int st[1000000];
int en[1000000];
int t;

void DFS(int n) {
    t++;
    st[n] = t;
    int s = G[n].size();
    for (int i = 0; i < s; i++) {
        if (st[G[n][i]] == intmax) {
            DFS(G[n][i]);
        }
    }
    t++;
    en[n] = t;
}

int main() {
    int N;
    cin >> N;
    V = N;
    fill(st, st + V + 10, intmax);
    fill(en, en + V + 10, intmax);
    t = 0;
    for (int i = 0; i < N; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int n;
            cin >> n;
            G[i].push_back(n - 1);
        }
    }
    for (int i = 0; i < N; i++) {
        if (st[i] == intmax) {
            DFS(i);
        }
    }
    for (int i = 0; i < N; i++) {
        cout << i + 1 << " " << st[i] << " " << en[i] << endl;
    }
}