Go: package main

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

var N int
var A [][]int
var t int
var color, d, f []int

const (
	WHITE = iota
	GRAY
	BLACK
)

func dfsVisit(u int) {
	color[u] = GRAY
	t ++
	d[u] = t
	for v:=0; v<N; v++ {
		if A[u][v] == 0 {
			continue
		}
		if color[v] == WHITE {
			dfsVisit(v)
		}
	}
	color[u] = BLACK
	t++
	f[u] = t
}

func dfs() {
	for u:=0; u<N; u++ {
		if color[u] == WHITE {
			dfsVisit(u)
		}
	}
	for u:=0; u<N; u++{
		fmt.Printf("%d %d %d\n", u+1, d[u], f[u])
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	color = make([]int, N)
	d = make([]int, N)
	f = make([]int, N)
	A = make([][]int, N)
	for i:=0; i<N; i++{
		A[i] = make([]int, N)
	}
	for i:=0; i<N; i++{
		index := nextInt(scanner) - 1
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			v := nextInt(scanner) - 1
			A[index][v] = 1
		}
	}
	dfs()
}

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 <bits/stdc++.h>
using namespace std;

using ll = long long;
#define REP(i, n) for(int (i)=0; (i)< (n); ++i)
#define REPR(i, n) for(int (i)=(n); (i)>=0; --i)
#define FOR(i, n, m) for(int (i)=(n); (i)<(m); ++i)

int n;
vector<int> d, f;
vector<vector<int>> g;
int Time = 0;
void dfs(int v){
  d[v] = ++Time;
  REP(i, g[v].size()){
    int nv = g[v][i];
    if(d[nv] != -1) continue;
    dfs(nv);
  }
  f[v] = ++Time;
}

int main(){
  cin >> n;
  d.resize(n,-1), f.resize(n), g.resize(n);
  REP(i, n){
    int u, k;
    cin >> u >> k;
    g[i].resize(k);
    REP(j, k){
      cin >> g[i][j];
      g[i][j]--;
    }
  }
  REP(i, n){
    if(d[i] == -1){
      dfs(i);
    }
  }
  REP(i, n){
    cout << i+1 << " " << d[i] <<" " <<  f[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <climits>

using namespace std;

const int WHITE=0, GRAY=1, BLACK=2;

struct DFS {
    int n;
    vector<vector<int>> g;
    vector<int> discover;
    vector<int> finish;
    vector<int> state;
    int time = 1;
    
    DFS(int n):n(n) {
        g.assign(n, vector<int>());
        discover.assign(n, -1);
        finish.assign(n, -1);
        state.assign(n, WHITE);
    }
    
    void addEdge(int u, int v) {
        g[u].push_back(v);
    }
    
    void solve() {
        for (int i = 0; i < n; i++) {
            if (state[i] == WHITE) {
                dfs(i);
            }
        }
    }
    
    void dfs(int u) {
        discover[u] = time++;
        for (int v : g[u]) {
            if (state[v] == WHITE) {
                state[v] = GRAY;
                dfs(v);
            } 
        }
        finish[u] = time++;
        state[u] = BLACK;
    }
    
    void print() {
        for (int i = 0; i < n; i++) {
            cout << i << ":";
            for (int v : g[i]) {
                cout << v << " ";
            }
            cout << endl;
        }
    }
};

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    DFS dfs(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--;
           dfs.addEdge(u, v);
       }
    }
    
    //dfs.print();
    
    dfs.solve();
    
    for (int i = 0; i < n; i++) {
        cout << (i + 1) <<  " " << dfs.discover[i] << " " << dfs.finish[i] << endl; 
    }
    
    return 0;
}

C++: #include <iostream>

using namespace std;

const int N = 100;
int A[N][N] = {{0}};

int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int u;
        cin >> u;

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

    for (int i = 0; i < n; ++i) {
        int j = 0;
        for (; j < n-1; ++j) {
            cout << A[i][j] << " ";
        }
        cout << A[i][j] << endl;
    }

    return 0;
}

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];

//按编号顺序获取与u相邻的v
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;
}