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<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];//グラフ情報
int color[N],d[N],f[N],tt;
int nt[N];

//uに隣接するvを番号順に取得
int next(int u){
    for(int v = nt[u]; v < n;v++){
        nt[u] = v + 1 ;
        if(M[u][v]) return v;
    }
    return -1;
}

//深さ優先探索
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(){
    //初期化
    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 <iostream>
#include <vector>
#include <stack>

using namespace std;

int main(){
    stack<int> st;
    int n;
    cin >> n;
    int d[n] = {};
    int f[n] = {};
    int vnum[n][2] = {};
    bool vflag[n] = {};
    int tmp2;
    int num;
    vector<vector<int>> vertex;
    vector<vector<bool>> explored;
    vector<int> tmp;
    vector<bool> flag;
    for(int i=0;i<n;i++){
        cin >> num;
        cin >> num;
        vnum[i][0] = num;
        for(int j=0;j<num;j++){
            cin >> tmp2;
            tmp.push_back(tmp2);
            flag.push_back(false);
        }
        if(n==0){
            flag.push_back(false);
        }
        vertex.push_back(tmp);
        explored.push_back(flag);
        tmp.clear();
        flag.clear();
    }
    int cnt = 1;
    int s;
    st.push(0);
    while(!st.empty()){
        s = st.top();

        if((vnum[s][0]==0) && d[s]==0){
            vflag[s] = true;
            d[s] = cnt++;
            f[s] = cnt++;
            st.pop();
        }else if(vnum[s][0]==vnum[s][1]){
            vflag[s] = true;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[vertex[s][vnum[s][1]]-1] && f[vertex[s][vnum[s][1]]-1]!=0 && d[s]==0){
            vflag[s] = true;
            d[s] = cnt++;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[vertex[s][vnum[s][1]]-1]){
            vflag[s] = true;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[s]){
            st.push(vertex[s][vnum[s][1]] - 1);
            vnum[s][1]++;
        }else{
            vflag[s] = true;
            d[s] = cnt++;
            st.push(vertex[s][vnum[s][1]] - 1);
            vnum[s][1]++;
        }
    }

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

C++: #include <stdio.h>
#include <iostream>
#include <algorithm>
#include <math.h>
#include <stack>

using namespace std;

int common_time=1,n;

int table[101][101],time_table[101][2];

void func(int node){
	if(time_table[node][0] == 0){
		time_table[node][0] = common_time++;
	}else{
		return;
	}
	for(int i=1;i<=n;i++){
		if(table[node][i] == 1){
			func(i);
		}
	}
	time_table[node][1] = common_time++;
}

int main(){
	int row,num,col;
	scanf("%d",&n);

	for(int i=1;i<=n;i++){
		for(int k=1;k<=n;k++){
			table[i][k]=0;
		}
		time_table[i][0]=0;
		time_table[i][1]=0;
	}

	for(int i=1;i<=n;i++){
		scanf("%d %d",&row,&num);
		for(int k=1;k<=num;k++){
			scanf("%d",&col);
			table[row][col]=1;
		}
	}

	for(int i=1;i<=n;i++){
		func(i);
	}

	for(int i=1;i<=n;i++){
		printf("%d %d %d\n",i,time_table[i][0],time_table[i][1]);
	}

    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];

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 <iostream>
#include <vector>
#include <unordered_set>
#include <unordered_map>
//#include "../cxx-prettyprint/prettyprint.hpp"

int timer = 0;
std::unordered_map<int, std::vector<int>> Adj;
std::unordered_set<int> nodes_visited;
std::unordered_map<int, int> discovered_time;
std::unordered_map<int, int> finished_time;

int dfs(int u) {
    nodes_visited.insert(u);
    discovered_time[u] = ++timer;
    for (int v : Adj[u]) {
        if (nodes_visited.find(v) == nodes_visited.end()) {
            dfs(v);
        }
    }
    finished_time[u] = ++timer;
}

int main() {
    int n;
    std::cin >> n;

    for (int i = 0; i < n; i ++) {
        int u, k;
        std::cin >> u >> k;
        std::vector<int> V(k);
        for (auto& v : V) {
            std::cin >> v;
        }
        Adj[u] = V;
    }

    dfs(1);

    for (int i = 1; i <= n; i ++) {
        std::cout << i << " " << discovered_time[i]
            << " " << finished_time[i] << std::endl;
    }
}