Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

C++: #include <stack>
#include <stdio.h>
#include <vector>

using namespace std;

#define NMAX 100
#define NIL -1

int d[NMAX + 1];           // start time, 1-origin
int f[NMAX + 1];           // finish time, 1-origin
stack<int> S;              // visited but not finished
vector<int> adj[NMAX + 1]; // adj
int n = 0;
int cnt = 0;

int next_unvisited_adj(int u) { // next not visited adj of u
    for (vector<int>::iterator it = adj[u].begin(); it != adj[u].end(); it++) {
        if (d[*it] == 0) // not finished
            return *it;
    }
    return NIL;
}

int next_unvisited() {
    for (int i = 1; i <= n; i++) {
        if (d[i] == 0)
            return i;
    }
    return NIL;
}

void dfs() {
    int x; // start vertex
    while ((x = next_unvisited()) != NIL) {
        // printf("dfs component of %d\n", x);
        S.push(x);
        d[x] = ++cnt;
        while (!S.empty()) { // dfs this component
            // check if the last visited guy is finished
            // if yes, pop it from the stack
            // if no, push the next unfinished adj of it
            int u = S.top();
            // printf("u=%d\n", u);
            int v = next_unvisited_adj(u);
            if (v != NIL) {
                if (d[v] == 0) { // v is not visited
                    // printf("%d is found\n", v);
                    d[v] = ++cnt;
                    S.push(v);
                }
            } else { // u is finished
                // printf("%d is finished\n", u);
                S.pop();
                f[u] = ++cnt;
            }
        }
    }
}

int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        d[i] = 0; // not visited
        f[i] = 0; // not finished
    }
    for (int i = 0; i < n; i++) {
        int u, k, v;
        scanf("%d", &u);
        scanf("%d", &k);
        for (int j = 0; j < k; j++) {
            scanf("%d", &v);
            adj[u].push_back(v);
        }
    }
    dfs();
    for (int i = 1; i <= n; i++) {
        printf("%d %d %d\n", i, d[i], f[i]);
    }

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define N_MAX 100
#define WH 0
#define GR 1
#define BK 2

long n;
long ttime = 0;
long G[N_MAX][N_MAX] = {};
long D[N_MAX], F[N_MAX];
long color[N_MAX] = {};

void dfs_rec(long u) {
    color[u] = GR;
    ttime++;
    D[u] = ttime;
    // cout << "start time " << u << ": " << D[u] << endl;

    for (long v = 0; v < n; v++) {
        // cout << "(u, v) = (" << u << ", " << v << ")" << endl;
        if (G[u][v] == 1 && color[v] == WH) {
            dfs_rec(v);
        }
    }
    color[u] = BK;
    ttime++;
    F[u] = ttime;
    // cout << "end time " << u << ": " << F[u] << endl;
}

int main() {
    long v_from, deg_out, v_to;

    cin >> n;
    for (long i = 0; i < n; i++) {
        cin >> v_from >> deg_out;
        v_from--;
        for (long j = 0; j < deg_out; j++) {
            cin >> v_to;
            v_to--;
            G[v_from][v_to] = 1;
        }
    }

    // for (long i = 0; i < n; i++) {
    //     for (long j = 0; j < n; j++) {
    //         if (j != 0) { cout << " "; }
    //         cout << G[i][j];
    //     }
    //     cout << endl;
    // }

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

    for (long i = 0; i < n; i++) {
        cout << i + 1 << " " << D[i] << " " << F[i] << endl;
    }

    return 0;
}