Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>

using namespace std;

#define N_MAX 100

int Adj[N_MAX][N_MAX] = {};
int Chk[N_MAX][2] = {};
int search_time = 1;

void dfs(int v, int num_node);

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

    cin >> n;

    //??£??\???????????????
    for (i = 0; i < n; i++) {
        cin >> u >> k;
        while (k-- > 0) {
            cin >> v;
            Adj[u-1][v-1] = 1;
        }
    }
/*
    cout << "show Adjacency matrix" << endl;
    for (i = 0; i < n; i++) {
        for (j = 0; j < n ; j++) {
            if (j == n - 1)
                cout << Adj[i][j] << endl;
            else
                cout << Adj[i][j] << ' ';
        }
    }
*/
    //??¢?´¢??????
//    dfs(1, n);
    for (i = 1; i <= n; i++) {
        if (Chk[i-1][0] == 0)
            dfs(i, n);
    }

    //????????????
    for(i = 1; i <= n; i++) {
        cout << i << ' ' << Chk[i-1][0] << ' ' << Chk[i-1][1] << endl;
    }

    return 0;
}

void dfs(int v, int num_node) {

//    cout << "dfs node : " << v << " time : " << search_time << endl;

    int i;
    //v???????????????????¨????
    if (Chk[v-1][0] == 0) //????????????node?????´???
        Chk[v-1][0] = search_time++;
    else {                //??¢??\???node?????´???
    //    search_time++;
        return;
    }

    //v???????????¢?´¢
    for (i = 1; i <= num_node; i++) {
        if (Adj[v-1][i -1] == 1) {
            dfs(i, num_node);
        }
    }

    //?????±??¨?????§??¢?´¢??????????????????
    //v???????????????????¨????
    Chk[v-1][1] = search_time++;
}

C++: #include <iostream>
#include <stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GREY = 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] = GREY;
	d[r] = ++tt;

	while (!S.empty()) {
		int u = S.top();
		int v = next(u);
		if (v != -1) {
			if (color[v] == WHITE) {
				color[v] = GREY;
				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 >> u;
	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 <iostream>
#include <stack>

using namespace std;

static const int N = 100;
static const int YET = 0;
static const int ALREADY = 1;

int main(void) {
  int M[N][N];
  int state[N];
  int timeTable[N][2];

  stack<int> st;

  int timeCount = 0;
  int n, u, k, v;

  cin >> n;

  //?????????
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }

  //Graph -> Matrix
  for(int i = 0; i < n; i++) {
    cin >> u >> k;
    u--;//0-origian
    for(int j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    } 
  }

  st.push(0);
  int currentV;
  while(!st.empty()) {
    timeCount++;
    currentV = st.top();
    st.pop();

    if(state[currentV] == YET) {
      timeTable[currentV][0] = timeCount;
      state[currentV] = ALREADY;
      st.push(currentV);

      for(int i = N; i > -1; i--) {
        if(M[currentV][i] == 1 && state[i] == YET) {
          st.push(i);
        }
      }
    }
    else if(timeTable[currentV][1] == 0){
      timeTable[currentV][1] = timeCount;
    }
    else {
      timeCount--;
    }
  }


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

C++: #include<bits/stdc++.h>
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3f
#define EPS (1e-10)
#define rep(i,n)for(int i=0;i<n;i++)
using namespace std;
typedef long long ll;
typedef pair<int, int>P;

vector<int>E[100];
int s[100], g[100];
bool used[100];
int t;

void dfs(int u) {
	used[u] = true;
	s[u] = ++t;
	for (int v : E[u]) {
		if (!used[v])dfs(v);
	}
	g[u] = ++t;
}
int main() {
	int n; scanf("%d", &n);
	rep(i, n) {
		int u, k; scanf("%d%d", &u, &k); u--;
		rep(j, k) {
			int v; scanf("%d", &v); v--;
			E[u].push_back(v);
		}
	}
	rep(i, n) {
		if (!used[i])dfs(i);
	}
	rep(i, n) {
		printf("%d %d %d\n", i + 1, s[i], g[i]);
	}
}

C++: #if 0
以前の反省を踏まえて、idの扱いを早いうちに決めてよかった
#endif

#include <iostream>
#include <vector>
using namespace std;

int curtime = 0, INF = 10000 * 100000 + 100;
struct result
{
    int reach_time;
    int back_time;
};
result res[110];
struct nodeData
{
    int id;
    vector<int> nodes;
};
vector<nodeData> dataSet;

// idはは1から
// for文は1から回す
vector<int> getNodes(int id)
{
    return dataSet[id - 1].nodes;
}

void dfs(int cur)
{
    // curの訪問時刻を記録
    curtime += 1;
    res[cur].reach_time = curtime;
    vector<int> nodes = getNodes(cur);
    for (int i = 0; i < nodes.size(); i++)
    {
        int node = nodes[i];
        if (res[node].reach_time == INF)
        {
            // 未訪問の場合
            dfs(node);
        }
    }
    curtime += 1;
    res[cur].back_time = curtime;
}

int main()
{
    // 初期化
    int /* 頂点数 */ n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        nodeData temp;
        temp.id = i;
        int id, /* 出次数 */ appear;
        cin >> id >> appear;
        for (int j = 1; j <= appear; j++)
        {
            int node;
            cin >> node;
            temp.nodes.push_back(node);
        }
        dataSet.push_back(temp);
        res[i].reach_time = INF;
    }

    // 処理
    for (int i = 1; i <= n; i++)
    {
        if (res[i].reach_time == INF)
        {
            dfs(i);
        }
    }
    for (int i = 1; i <= n; i++)
    {
        cout << i << " " << res[i].reach_time << " " << res[i].back_time << endl;
    }
}