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 <bits/stdc++.h>
using namespace std;
#ifdef ENABLE_DEBUG_OUTPUT
#define DEBUG_LOG(s) cout << s << endl;
#else
#define DEBUG_LOG(s) void();
#endif

int t = 1;
vector<vector<bool>> g;
vector<int> d;
vector<int> f;

void dfs(const int s) {
    if(d[s] != -1) return;
    d[s] = t++;

    for (auto i = 0; i < (int)g[s].size(); i++) {
        if(g[s][i]) dfs(i);
    }

    f[s] = t++;
}

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

    g.assign(n, vector<bool>(n, false));
    for (auto i = 0; i < n; i++) {
        int u, k; cin >> u >> k;
        for (auto j = 0; j < k; j++) {
            int v; cin >> v;
            g[u - 1][v - 1] = true;
        }
    }

    d.assign(n, -1);
    f.assign(n, -1);
    for (auto i = 0; i < n; i++) {
        if(d[i] == -1) dfs(i);
    }

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

    return 0;
}

C++: #include <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
typedef int long long ll;
static const int N=100;
static const int white=0;
static const int gray=1;
static const int black=2;

int n,d[N],f[N],tt;
int color[N],nt[N];
int mp[N][N];

int next(int u){
    
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;
        if(mp[u][v]!=0)return v;
    }
    return -1;
}


void dfs_visit(int r){
    
   
    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){
            d[v]=++tt;
            color[v]=gray;
            s.push(v);
            }
        }else{
            color[u]=black;
            f[u]=++tt;
            s.pop();
        }
    }
}



void dfs(){

    rep(i,n){color[i]=white;nt[i]=0;}
    tt=0;
    
    for(int i=0;i<n;i++){
        if(color[i]==white){
            dfs_visit(i);
        }
    }
    rep(i,n){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    
}

int main(){
    cin>>n;
    
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            mp[i][j]=0;
        }
    }
    for(int i=0;i<n;i++){
        int a,b;
        cin>>a>>b;
        rep(j,b){
            int c;
            cin>>c;
            mp[a-1][c-1]=1;
        }
    }
    
    dfs();
    
    return 0;
}

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

struct VRTX {
	int dt, ft, v[101];
};

int curtime = 1;
VRTX ver[101];

void depthFirstSearch(int u);

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

	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> u >> k;
		for (j = 0; j < k; j++) {
			cin >> ver[u].v[j];
		}
	}
	
	for (i = 1; i <= n; i++) {
		depthFirstSearch(i);
	}

	for (i = 1; i <= n; i++) {
		cout << i << " " << ver[i].dt << " " << ver[i].ft << endl;
	}

	return 0;
}

void depthFirstSearch(int u) {

	if (ver[u].dt == 0) {
		int i = 0;

		ver[u].dt = curtime++;

		while (ver[u].v[i] != 0) {
			depthFirstSearch(ver[u].v[i]);
			i++;
		}

		ver[u].ft = curtime++;

		return;
	}
	return;
}

C++: #include <cassert>
#include <algorithm>
#include <iostream>
#include <vector>
#include <string>

class TVertex
{
    int FIndex;
    std::vector<TVertex*> FList;
    int FDiscoveryTime;
    int FFinishTime;

public:
    TVertex(int Index)
     : FIndex(Index), FDiscoveryTime(0), FFinishTime(0)
    {}
    void AddPath(TVertex* Vertex)
    {
        FList.push_back(Vertex);
    }
    void PrintTime(std::ostream& out)const
    {
        out << FIndex << " " << FDiscoveryTime << " " << FFinishTime << std::endl;
    }
    int DepthFirstSearch(int Time)
    {
        if(FDiscoveryTime) return Time;
        FDiscoveryTime = Time++;
        for(std::vector<TVertex*>::iterator It = FList.begin(); It != FList.end(); ++It){
            TVertex* V = *It;
            Time = V->DepthFirstSearch(Time);
        }
        FFinishTime = Time++;
        return Time;
    }
};
class TGraph
{
    std::vector<TVertex*> FTable;
    void Init(int n)
    {
        assert(n > 0);
        FTable.resize(n);
        for(int i = 0; i < n; ++i){
            FTable[i] = new TVertex(i);
        }
    }
public:
    TGraph(int n)
    {
        Init(n+1);
    }
    
    void SetupVertex(std::istream& in)
    {
        int Index;
        in >> Index;
        assert(Index >= 1);
        assert(Index <= FTable.size());
        int k;
        in >> k;
        for(int i = 0; i < k; ++i){
            int v;
            in >> v;
            FTable[Index]->AddPath(FTable[v]);
        }
    }
    void DepthFirstSearch()
    {
        int Time = 1;
        for(int i = 1; i < FTable.size(); ++i){
            Time = FTable[i]->DepthFirstSearch(Time);
        }
    }
    void PrintTime(std::ostream& out)
    {
        for(int i = 1; i < FTable.size(); ++i){
            FTable[i]->PrintTime(out);
        }
    }
};

int main()
{
    int n;
    std::cin >> n;
    TGraph Graph(n);
    for(int i = 0; i < n; ++i){
        Graph.SetupVertex(std::cin);
    }
    Graph.DepthFirstSearch();
    Graph.PrintTime(std::cout);
    return 0;
    
}

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

using i64 = int64_t;

using Graph = vector<vector<int>>;

int dfs(int u, int t, vector<pair<int, int>> &ans, const Graph &graph){
    ans[u].first = t;
    for(auto v: graph[u]){
        if(ans[v].first == -1){
            t = dfs(v, t+1, ans, graph);
        }
    }
    ans[u].second = t + 1;
    return t + 1;
}

int main(){
    int n;
    cin >> n;
    Graph graph(n+1, vector<int>());
    for(int i=0;i<n;++i){
        int u, k;
        cin >> u >> k;
        for(int j=0;j<k;++j){
            int v;
            cin >> v;
            graph[u].push_back(v);
        }
    }
    vector<pair<int, int>> ans(n+1, make_pair(-1, -1));
    int t = 0;
    for(int u=1;u<=n;++u){
        if(ans[u].first == -1)
            t = dfs(u, t+1, ans, graph);
    }
    for(int i=1;i<=n;++i){
        cout << i << " " << ans[i].first << " " << ans[i].second << endl;
    }

    return 0;
}