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++: #include <iostream>
#include <queue>

using namespace std;

int G[100][100];
int In[100];
int Out[100];
void init() {
	for (int i = 0; i < 100; i++) {
		for(int j = 0; j < 100; j++)
			G[i][j] = 0;
		In[i] = -1;
		Out[i] = -1;
	}	
}

void dfs(int src);

int main() {
	init();
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int v_j;
			cin >> v_j;
			G[u - 1][v_j - 1] = 1;
		}
	}
	dfs(0);
	for (int i = 0; i < n; i++)
		cout << i + 1 << " " << In[i] << " " << Out[i] << endl;
}

int t = 1;

void dfs(int cur) {
	In[cur] = t;
	t++;
	for (int dst = 0; dst < 100; dst++)
		if (G[cur][dst] == 1 && In[dst] == -1)
			dfs(dst);
	Out[cur] = t;
	t++;
}

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

#define N 100
// 未訪問
#define WHITE 0
// 訪問中
#define GRAY 1
// 訪問済み
#define BLACK 2

int n,M[N][N];
int color[N];
// 訪問時間
int d[N];
// 探索終了時間
int f[N];
// 時間
int t = 0;
// 探索済みの頂点を一から探索しないように、nt[u]にすでに探索済みの番号を入れ、次回は探索した移行の頂点から探索されるようにする
int nt[N];

/**
    uに隣接するvを番号順に取得する
*/
int next(int u){
    // 探索済み移行の頂点から探索を始める
    for(int v = nt[u];v < n;++v){
        nt[u] = v + 1;
        if(M[u][v]){
            return v;
        }
    }
    return -1;
}

/**
    スタックを用いた深さ優先探索
*/
void dfs(int u){
    for(int i = 0;i < n;++i){
        nt[i] = 0;
    }
    
    stack<int> S;
    S.push(u);
    color[u] = GRAY;    // 訪問中
    d[u] = ++t;      // 訪問時間
    
    while(!S.empty()){
        int topU = S.top();
        // 隣接する頂点
        int v = next(topU);
        // 隣接する頂点が見つかった場合
        if(v != -1){
            // 未探索のケース
            if(color[v] == WHITE){
                color[v] = GRAY;
                // 訪問時間
                d[v] = ++t;
                S.push(v);
            }
        }else{
            // 未訪問の頂点が見つからなかった
            S.pop();
            // 探索終了
            color[topU] = BLACK;
            // 探索終了時間
            f[topU] = ++t;
        }
    }
}

int main(){
    int u,k,v;
    cin >> n;
    
    // 初期化
    for(int i = 0;i < n;++i){
        color[i] = WHITE;
        for(int j = 0;j < n;++j){
            M[i][j] = 0;
        }
    }
    
    for(int i = 0;i < n;++i){
        cin >> u >> k;
        // 頂点を移動する
        u--;
        // 頂点の数だけ回す
        for(int j = 0;j < k;++j){
            cin >> v;
            --v;    // ずらす
            M[u][v] = 1;
        }
    }
    for(int i = 0;i < n;++i){
        if(color[i] == WHITE){
            dfs(i);
        }
    }
    
    for(int i = 0;i < n;++i){
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <algorithm>
#include <array>
#include <stack>
#include <map>

using namespace std;

template<typename ISTREAM>
void readGraphListAsMatrix(const size_t n, ISTREAM& cin, vector< vector<int> >& graphMatrix) {
	graphMatrix = vector< vector<int> >(n, vector<int>(n, 0));
	for (size_t i = 0; i != n; ++i) {
		size_t u;
		size_t k;
		cin >> u;
		cin>> k;
		for (size_t j = 0; j != k; ++j) {
			size_t v;
			cin >> v;
			graphMatrix.at(u - 1).at(v - 1) = 1;
		}
	}
}

void printMatrix(const vector< vector<int> >& grapthMatrix) {
	const size_t n = grapthMatrix.size();
	for (size_t i = 0; i != n; ++i) {
		const vector<int>& adj = grapthMatrix.at(i);
		cout << adj.front();
		for (size_t j = 1; j != n; ++j) {
			cout << " " << adj.at(j);
		}
		cout << endl;
	}
}


template<typename T>
void execute(T& cin) {
	size_t n;
	cin >> n;
	vector< vector<int> > graphMatrix;
	readGraphListAsMatrix(n, cin, graphMatrix);
	stack<int> visitedNodeIDs;
	int time = 0;
	vector<pair<int, int>> timeStamp(n,make_pair(0,0));//pair<初回訪問時刻, 完了時刻>
	vector<vector<int>::iterator> searchBeginPos; {
		searchBeginPos.reserve(n);
		for (auto& v : graphMatrix)searchBeginPos.push_back(v.begin());
	}

	vector<pair<int, int>>::iterator visitTimeSearchPos = timeStamp.begin();
	while (
		(visitTimeSearchPos = find_if(visitTimeSearchPos, timeStamp.end(), [&](const pair<int, int>& df) {return df.first == 0; }))
		!= timeStamp.end()) {
		visitedNodeIDs.push(distance(timeStamp.begin(), visitTimeSearchPos));
		visitTimeSearchPos->first = ++time;
		++visitTimeSearchPos;
		while (!visitedNodeIDs.empty()) {
			const int nodeID_1 = visitedNodeIDs.top();
			vector<int>& neighbourNodeList = graphMatrix.at(nodeID_1);
			vector<int>::iterator result = find(searchBeginPos.at(nodeID_1), neighbourNodeList.end(), 1);
			if (result != neighbourNodeList.end()) {
				const int nextVisitID_1 = distance(neighbourNodeList.begin(), result);
				timeStamp.at(nextVisitID_1).first = time + 1;
				for (auto&v : graphMatrix) v.at(nextVisitID_1) = 0;
				visitedNodeIDs.push(nextVisitID_1);
				searchBeginPos.at(nodeID_1) = result + 1;
			}
			else {
				//隣接リストに検索対象なし
				timeStamp.at(nodeID_1).second = time + 1;
				visitedNodeIDs.pop();
			}
			++time;
		}
	}
	for (int i = 0; i != n; ++i) {
		cout << i + 1 << " " << timeStamp.at(i).first << " " << timeStamp.at(i).second << endl;
	}
}

int main()
{

	execute(cin);

	return 0;
}

C++: // C++ 14
#include <iostream>
#include <vector>
#include <array>
#include <list>
#include <algorithm>
#include <queue>
#include <stack>
#include <math.h>

#define ll long long
#define Int int
#define INTMAX (1 << 21)
#define loop(x, start, end) for(Int x = start; x < end; x++)
#define loopdown(x, start, end) for(Int x = start; x > end; x--)

using namespace std;

#define MAX 100


void dfs(vector<Int> vs[], Int n) {
    Int t = 0;
    bool visited[n];
    Int ds[n];
    Int fs[n];
    
    loop(i,0,n) {
        visited[i] = false;
        ds[i] = fs[i] = 0;
    }
    
    stack<Int> S;
    loop(i,0,n) {
        if (visited[i]) continue;
        
        S.push(i);
        visited[i] = true;
        ds[i] = ++t;
    
loop:
        while (!S.empty()) {
            Int i = S.top();
            for (auto c: vs[i]) {
                if (visited[c]) continue;
                S.push(c);
                visited[c] = true;
                ds[c] = ++t;
                goto loop;
            }
            
            S.pop();
            fs[i] = ++t;
        }
    }
    
    loop(i,0,n) cout << i+1 << " " << ds[i] << " " << fs[i] << endl;
}


int main(void){
    Int n, x, cc, c;
    cin >> n;
    vector<Int> vs[n];
    loop(i,0,n) {
        cin >> x >> cc;
        loop(j,0,cc) {
            cin >> c;
            vs[x-1].push_back(c-1);
        }
        
    }
    dfs(vs, n);
}