Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

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

using namespace std;

const int WHITE = 0, GREY = 1, BLACK = 2;

struct DFS {
    int n;
    vector<vector<int>> g;
    vector<int> color;
    vector<int> dt;
    vector<int> ft;
    int ct = 1;
 
    DFS(int n) : n(n) {
        g.assign(n, vector<int>());
        color.assign(n, WHITE);
        dt.assign(n, -1);
        ft.assign(n, -1);
    }
    
    void solve() {
        for (int i = 0; i < n; i++) {
            if (color[i] == WHITE) {
                dfs(i);
            }
        }
    }
    
    void dfs(int u) {
        //cout << "visit " << u << endl;
        color[u] = GREY;
        dt[u] = ct++; 
        for (int v : g[u]) {
            if (color[v] == WHITE) {
                dfs(v);
            }
        }
        ft[u] = ct++;
        color[u] = BLACK;
    }
    
    void addEdge(int u, int v) {
        g[u].push_back(v);
    }
    
    void printGraph() {
        for (int i = 0; i < n; i++) {
            cout << i << ": ";
            for (int v : g[i]) {
                cout << v << " ";
            }
            cout << endl;
        }
    }
        
};


int main() {   
    int n;
    cin >> n;
    DFS dfs(n);
   
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            v--;
            dfs.addEdge(u, v);
        }  
    }
    
    //dfs.printGraph();
    
    dfs.solve();
    
    for (int i = 0; i < n; i++) {
        cout << (i + 1) << " " << dfs.dt[i] << " " << dfs.ft[i] << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <cstring>
#define N 101

using namespace std;

int visited[N], discovery[N], finish[N], tt, n;
vector<int> G[N];

void dfs(int u) {
    visited[u] = 1;
    discovery[u] = ++tt;
    for (int i = 0; i < G[u].size(); i++) {
        if (visited[G[u][i]] == 0) {
            dfs(G[u][i]);
        }
    }
    finish[u] = ++tt;
}

int main() {
    int u, k, v;

    cin >> n;

    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }
    memset(visited, 0, sizeof(visited));
    tt = 0;

    for (int i = 0; i < n; i++) {
        if (visited[i] == 0) {
            dfs(i);
        }
    }

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

    return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class Graph{
public:
  int v;
  int ftime = -1;
  int ltime = -1;
  vector<int> e;
};
vector<Graph> g;
int cnt = 0;
void dfs(int pos){
  if( g[pos].ftime != -1 ) return;
  cnt++;
  g[pos].ftime = cnt;
  for(int i=0; i<g[pos].e.size(); i++){
    dfs(g[pos].e[i]);
  }
  cnt++;
  g[pos].ltime = cnt;
}

int main(void) {

  int n;
  cin >> n;
  g.resize(n);
  int u, k;
  for(int i=0; i<n; i++){
    cin >> u >> k;
    u--;
    g[u].v = u;
    g[u].e.resize(k);
    for(int j=0; j<k; j++){
      cin >> g[u].e[j];
      g[u].e[j]--;
    }
    sort(g[u].e.begin(), g[u].e.end());
  }
  for(int i=0; i<n; i++) dfs(i);
  for(int i=0; i<n; i++){
    cout << g[i].v + 1 << " " << g[i].ftime << " " << g[i].ltime << endl;
  }



  return 0;
}

// EOF

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

using namespace std;

int tim = 0;
vector<vector<int>> to;
vector<bool> reached;
vector<int> d;
vector<int> f;



void dfs(int point);

int main()
{
    int n;
    cin >> n;
    to.resize(n+1);
    for(int i = 1; i <= n; i++){
        int m;
        cin >> m;
        cin >> m;
        to[i].resize(m);
        for(int j = 0; j < m; j++){
            cin >> to[i][j];
        }
    }
    
    reached.resize(n+1);
    d.resize(n+1);
    f.resize(n+1);

    for(int i = 1; i <=n; i++){
        if(!reached[i]){
            dfs(i);
        }
    }

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

    return 0;
}

void dfs(int point)
{
    tim++;
    reached[point] = true;
    d[point] = tim;

    for(int i = 0; i < to[point].size(); i++){
        if(!reached[to[point][i]]){
            dfs(to[point][i]);
        }
    }
    tim++;
    f[point] = tim;    

}

C++: #include <cstdio>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;

using Weight=int;
using DArray=vector<Weight>;
using DMatrix=vector<DArray>;

static const Weight INF=1<<29;

struct Edge {
    size_t src, dst;
    Weight weight;
    Edge() {}
    Edge(size_t src, size_t dst, Weight weight=1):
        src(src), dst(dst), weight(weight)
    {}
};

bool operator<(const Edge &e, const Edge &f) {
    if (e.weight != f.weight) {
        return e.weight > f.weight;
    } else {
        return e.src!=f.src? e.src<f.src : e.dst<f.dst;
    }
}

using Edges=vector<Edge>;
using Vertex=vector<Edge>;
using Graph=vector<Vertex>;

void join(Graph &g, size_t s, size_t d, Weight w=1) {
    // non-directed
    g[s].push_back(Edge(s, d, w));
    g[d].push_back(Edge(d, s, w));
}

void connect(Graph &g, size_t s, size_t d, Weight w=1) {
    // directed
    g[s].push_back(Edge(s, d, w));
}

void dfs(const Graph &g, size_t v, int &t, vector<int> &d, vector<int> &f) {
    d[v] = t;
    for (const Edge &e: g[v])
        if (!d[e.dst])
            dfs(g, e.dst, ++t, d, f);

    f[v] = ++t;
}

int main() {
    size_t n;
    scanf("%zu", &n);

    Graph g(n);
    for (size_t i=0; i<n; ++i) {
        size_t k;
        scanf("%*d %zu", &k);
        for (size_t j=0; j<k; ++j) {
            size_t v;
            scanf("%zu", &v);
            --v;

            connect(g, i, v);
        }
    }

    vector<int> d(n), f(n);
    int t=1;
    for (size_t v=0; v<n; ++v)
        if (!d[v])
            dfs(g, v, t, d, f);

    for (size_t i=0; i<n; ++i)
        printf("%zu %d %d\n", i+1, d[i], f[i]);

    return 0;
}