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++: /* ALDS1_11_B: Depth First Search */

#include <iostream>
#include <cstdio>
#include <vector>
using std::vector;

vector<int> *graph;
int elapsed = 1;

// Search the graph recursively by depth-first search.
void traverse(int id, int found[], int finished[]) {
    if (0 < found[id]) {
        return;
    }

    found[id] = elapsed++;
    vector<int> adjs = graph[id];
    for (int i = 0; i < adjs.size(); i++) {
        traverse(adjs[i], found, finished);
    }
    finished[id] = elapsed++;
}

int main() {
    int n_v;
    scanf("%d", &n_v);

    int max_v = n_v + 1;
    graph = new vector<int>[max_v];

    for (int i = 0; i < max_v; i++) {
        int id, n_adjs;
        scanf("%d %d", &id, &n_adjs);

        for (int j = 0; j < n_adjs; j++) {
            int adj_id;
            scanf("%d", &adj_id);
            graph[id].push_back(adj_id);
        }
    }

    int found[max_v];
    int finished[max_v];
    std::fill_n(found, max_v, 0);
    std::fill_n(finished, max_v, 0);

    for (int id = 1; id < max_v; id++) {
        traverse(id, found, finished);
    }

    for (int id = 1; id < max_v; id++) {
        printf("%d %d %d\n", id, found[id], finished[id]);
    }
    return 0;
}

C++: #include<algorithm>
#include<bitset>
#include<iostream>
#include<iomanip>
#include<set>
#include<string>
#include<math.h>

using namespace std;

class zahyo{
	public:
	int x;
	int y;
	zahyo(){
		x=0;
		y=0;
	}
	zahyo(int x_,int y_){
		x=x_;
		y=y_;
	}
	void print(){
		cout<<x<<" "<<y;
	}
	zahyo operator+(zahyo add){
		add.x=this->x+add.x;
		add.y=this->y+add.y;
		return add;
	}
	zahyo operator-(zahyo add){
		add.x=this->x-add.x;
		add.y=this->y-add.y;
		return add;
	}
	bool operator==(const zahyo add) const{
		if(add.x==this->x and add.y==this->y){return true;}
		else{return false;}
	}
	bool operator!=(const zahyo add) const{
		if(add.x==this->x or add.y==this->y){return false;}
		else{return true;}
	}
	bool operator<(const zahyo add) const{
		if(this->x<add.x){return true;}
		else if(this->x==add.x and this->y<add.y){return true;}
		else{return false;}
	}
	bool operator>(const zahyo add) const{
		if(this->x>add.x){return true;}
		else if(this->x==add.x and this->y>add.y){return true;}
		else{return false;}
	}
	void input(){
		cin>>x>>y;
	}
};

int n;
int counter=0;
int glaph[100][100]={{}};
int ans[100][2]={{}};
void depthsearch(int t){
	counter++;
	ans[t][0]=counter;
	for(int i=0;i<n;i++){
		if(glaph[t][i]==1 and ans[i][0]==0){
			depthsearch(i);
		}
	}
	counter++;
	ans[t][1]=counter;
}

int main(){
	cin>>n;
	for(int i=0;i<n;i++){
		int k;
		cin>>k;
		cin>>k;
		for(int j=0;j<k;j++){
			int l;
			cin>>l;
			l--;
			glaph[i][l]=1;
		}
	}
	for(int i=0;i<n;i++){
		if(ans[i][0]==0){
			depthsearch(i);
		}
	}
	for(int i=0;i<n;i++){
		cout<<(i+1)<<" "<<ans[i][0]<<" "<<ans[i][1]<<endl;
	}
}

C++: #include <iostream>
#include <vector>

using namespace std;

void dfs(vector<vector<int>>& graph, int vertex, vector<bool>& marked, vector<int>& d, vector<int>& f, int& time) {
    if (marked[vertex])
        return;
    marked[vertex] = true;
    d[vertex] = ++time;
    for (int x: graph[vertex])
        if (!marked[x])
            dfs(graph, x, marked, d, f, time);
    f[vertex] = ++time;
}

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

    vector<vector<int>> graph;
    for (int i = 0; i < n; i++) {
        vector<int> t;
        int u;
        cin >> u;
        int k;
        cin >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            t.push_back(v - 1);
        }
        graph.push_back(t);
    }

    vector<bool> marked(n);
    vector<int> d(n);
    vector<int> f(n);
    int time = 0;

    for (int i = 0; i < n; i++)
        dfs(graph, i, marked, d, f, time);
    for (int i = 0; i < n; i++)
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;

    return 0;
}

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,g[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(g[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(void) {
    int u,k,v;
    cin>>n;
    for(int i=0;i<n;i++) {
        for(int j=0;j<n;j++) {
            g[i][j]=0;
        }
    }
    for(int i=0;i<n;i++) {
        cin>>u>>k;
        u--;
        for(int j=0;j<k;j++) {
            cin>>v;
            v--;
            g[u][v]=1;
        }
    }
    dfs();
    return 0;
}