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++: #if 0
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#endif
#include <iostream>
#include <queue>
using namespace std;
int D[105] = {0};
int V[105];
queue<int> Q[105];
int Ntime=0;
int n,u,k,v;
int d[105] = {0};//start time
int f[105] = {0};//end time
void dfs(int cur) { // cur????¨????
  // cur ????¨??????????????¨????
  Ntime += 1;
  // ???????¢??????¨??¨???
  //cerr << "visiting " << cur << ' ' << Ntime << endl;
  if(D[cur] == 0)
      d[cur] = Ntime;

  for(int dst = 1; dst <= n; dst++) { // ??¨???????????? dst ????????????
    if (D[cur] == 0&&Q[cur].size()>0 && Q[cur].front() == dst && D[dst] == 0) { // cur??????dst??????????????????,dst???????¨??????????
      if(dst != cur && d[dst] == 0)
          dfs(dst);
      Q[cur].pop();
	}
      if(D[cur] == 0&&Q[cur].size()>0 && Q[cur].front() == dst && D[dst] == 1)
          Q[cur].pop();
  }
  // cur ????¨????????????????????¨????
      Ntime += 1;
    if(D[cur] == 0){
        f[cur] =  Ntime;
        D[cur] = 1;}
  // ??¢??°?????????????????????????????? (?????¢??°)
}
int main(){
  cin >> n;
  for(int i = 1; i <= n; i++){
    cin >> u >> k;
    V[i] = i;
    for(int j = 1; j <= k; j++){
      cin >> v;
      Q[u].push(v);     
    }
  }

  for(int i = 1; i <= n; i++)
    if(D[i] == 0)
        dfs(V[i]);
  for(int i = 1; i <= n; i++){
    cout << V[i] <<" "<< d[i] <<" "<< f[i] <<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 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 = search(array, A, 1, n, 0);
    for(i=1;i<=n;i++)printf("%d %d %d\n",i,array[i].d,array[i].f);
    return 0;
}

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

using vvb = std::vector<std::vector<bool>>;

struct TimeStamp
{
    int discovered;
    int finished;
};

std::vector<TimeStamp> dfs(const vvb& edges)
{
    using namespace std;

    int time {1};
    const int n = edges.size();
    stack<int> st;
    vector<bool> reached(n);
    vector<TimeStamp> times(n);

    //すべての辺について行う
    for (int i = 0; i < n; ++i)
    {
        if (reached[i])
            continue;

        reached[i] = true;
        times[i].discovered = time++;
        st.push(i);
        
        //点jからつながるすべての辺を調べる
        while (!st.empty())
        {
            int top = st.top();
            for(int j = i + 1; j < n; ++j)
                if (!reached[j] && edges[top][j])
                {
                    reached[j] = true;
                    times[j].discovered = time++;
                    st.push(j);
                    break;
                }

            //その点からの探索候補がなければ前の点に戻る
            if (top == st.top())
            {
                times[top].finished = time++;
                st.pop();
            }
        }
    }

    return times;
}

void solve()
{
    using namespace std;

    int n;
    cin >> n;

    vvb edges(n, vector<bool>(n));

    //読み込み
    for (int i = 0; i < n; ++i)
    {
        int u, k;
        cin >> u >> k;

        for (int j = 0; j < k; ++j)
        {
            int v;
            cin >> v;
            edges[u - 1][v - 1] = true;
        }
    }

    auto times = dfs(edges);

    for (int i = 0; i < n; ++i)
    {
        cout << i + 1 << " " << times[i].discovered << " " << times[i].finished << endl;
    }
}

int main()
{
    solve();
    return 0;
}

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

int n;
vector< vector<int> > do_thi; 
bool *da_duyet;
int *d;
int *f;
int timestamp;

void dfs(int dinh_dang_duyet) { 
	d[dinh_dang_duyet] = timestamp++; // Danh dau so buoc bat dau duyet dinh
	da_duyet[dinh_dang_duyet] = true; // Danh dau dinh da duoc duyet
	// Tim nhung dinh lan can
	for (int i = 0, lan_can = 0; i < do_thi[dinh_dang_duyet].size(); ++i) {
		lan_can = do_thi[dinh_dang_duyet][i];
		if (da_duyet[lan_can]) continue;
		dfs(lan_can);
	}
	f[dinh_dang_duyet] = timestamp++; // Danh dau so buoc khi ket thuc viec duyet dinh do
}

int main() {
	cin >> n; // Sau khi co gia tri n cu the moi cap phat kich thuoc o nho cho cac mang
	da_duyet = new bool[n + 1]; // Cap phat mang danh dau dinh da duyet hay chua (vi mang chi so tinh tu 0)
	d = new int[n + 1]; // Cap phat mang de luu thoi diem tim ra cac dinh
	f = new int[n + 1]; // Cap phat mang de luu thoi diem duyet xong cac dinh
	
	for (int i = 0; i <= n; ++i) { // Khoi tao cac gia tri cho moi dinh
		do_thi.push_back(vector<int>()); // Khoi tao vector cho moi dinh
		da_duyet[i] = false; // Khoi tao trang thai da duyet hay chua cho moi dinh
		d[i] = 0; // Khoi tao thoi diem tim ra moi dinh
		f[i] = 0; // Khoi tao thoi diem duyet xong moi dinh
	}
	for (int i = 0, k = 0, u = 0, v = 0; i < n; ++i) { // Xay dung cac canh cua do thi
		cin >> u; // Doc vao ID cua dinh u
		cin >> k; // Doc vao so dinh ke voi u (bac cua dinh u)

		for (int j = 0; j < k; ++j) { // Doc vao cac dinh lan can cua u, dua vao do thi
			cin >> v; // Doc vao moi dinh lan can
			do_thi[u].push_back(v); // Dua vao vector bieu dien tinh tuong ung
		}
	}
	
//	for (int i = 1; i <= n; ++i) { // Sap xep lai cac dinh lan can cua dinh i
//		sort(do_thi[i].begin(), do_thi[i].end());
//	}
	
	timestamp = 1;
	
	for (int i = 1; i <= n; ++i) { // Duyet tat ca cac dinh cua do thi
		if (da_duyet[i]) continue; // Neu dinh da duyet thi kiem tra tiep
		dfs(i);	// Neu dinh chua duyet thi dua vao ham dfs
	}
	
	for (int i = 1; i <= n; ++i) { // In ra ket qua
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}