Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

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

using namespace std;

vector<int> d(101, -1), f(101, -1);
vector<vector<int> > c;

int n, u, k, v;
int dfs(int node, int time) {
    d[node] = time;
    for(int i=0; i<n; ++i) {
        if(c[node][i]==1&&d[i]==-1) time = dfs(i, time+1);
    }
    time++;
    f[node] = time;
    return time;
}

int main() {
    cin >> n;
    for(int i=0; i<n; ++i) {
        cin >> u >> k;
        vector<int> tmp(100, 0);
        for(int j=0; j<k; ++j) {
            cin >> v;
            tmp[v-1] = 1;
        }
        c.push_back(tmp);
    }

    bool isFinished = false;
    int node = 0;
    int time = 1;
    while(isFinished==false) {
        time = dfs(node, time);
        isFinished = true;
        for(node=0; node<n; node++) {
            if(d[node]==-1) {
                isFinished=false;
                break;
            }
        }
    }
    for(int i=0; i<n; ++i) {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
    return 0;
}

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

#define MAX 100
static const int WHITE = 0; // not visit
static const int GRAY = 1; // visited
static const int BLACK = 2; // searched

int n;
int M[MAX][MAX] = { 0 };
int color[MAX] = { WHITE };
int d[MAX], f[MAX], tt = 0;
int nt[MAX] = { 0 };

// get vertex next u
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 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;
	}
	return;
}

int main() {
	cin >> n;

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

	dfs();
	return 0;

}

C++: #include<bits/stdc++.h>
using namespace std;
static const int N=100;
enum COLOR{WHITE,GRAY,BLACK};

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,v,k,i,j;
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        for(j=0;j<n;j++)M[i][j]=0;
    }

    for(i=0;i<n;i++)
    {
        scanf("%d %d",&u,&k);
        u--;
        for(j=0;j<k;j++)
        {
            scanf("%d",&v);
            v--;
            M[u][v]=1;
        }
    }

    dfs();
 	return 0;
}

C++: #include <stdio.h>

#define VerticesNum 100
typedef unsigned int uint;

struct output
{
    uint uDiscoverTime;
    uint uFinTime;
}Output;

struct output gstOutput[VerticesNum];
uint uTotalTime = 1;

void DepthFirstSearch(uint pGraph[][VerticesNum], uint uSize, uint uRoot)
{
    if(gstOutput[uRoot].uDiscoverTime == 0)
    {
        gstOutput[uRoot].uDiscoverTime = uTotalTime++;
    }
    else
    {
        return;
    }
    
    for(uint i = 0; i < uSize; i++)
    {
        if((pGraph[uRoot][i] == 1) && (gstOutput[i].uDiscoverTime == 0 ))
        {
            DepthFirstSearch(pGraph, uSize, i);
        }
    }
    gstOutput[uRoot].uFinTime = uTotalTime++;
    
    return;
}

int main(void){
    uint arGraph[VerticesNum][VerticesNum] = {};
    
    uint uVertices;
    scanf("%u", &uVertices);
    
    for(uint i = 0; i < uVertices; i++)
    {
        uint uVertexIdx;
        uint OutDegree;
        scanf("%u", &uVertexIdx);
        scanf("%u", &OutDegree);
        for(uint j = 0; j < OutDegree; j++)
        {
            uint AdjacentVertex;
            scanf("%u", &AdjacentVertex);
            arGraph[uVertexIdx - 1][AdjacentVertex - 1] = 1; 
        }
    }
    /*
    for(uint i = 0; i < uVertices; i++)
    {
        for(uint j = 0; j < uVertices; j++)
        {
            printf("%u", stGraph[i][j]);
            (j < (uVertices - 1))
                ? printf(" ")
                : printf("\n");
        }
    }
    */
    for(uint uRoot = 0; uRoot < uVertices; uRoot++)
    {
        DepthFirstSearch(arGraph, uVertices, uRoot);
    }
    
    for(uint i = 0; i < uVertices; i++)
    {
        printf("%d %d %d\n", i + 1, gstOutput[i].uDiscoverTime, gstOutput[i].uFinTime);
    }
    
    return 0;
}