Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveDfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: #include<iostream>
int main(){

  int n,a;
  std::cin>>n;

  int Adj[100][100],adj[100][100]={0},find[100][2],back[100][100],depth[100]={0},endflag[100]={0},flag;
	int u[n],k[n],kcou=0,timenow=0,v,pred,prev,firstv,backcount[100]={0};
  for(int i=0;i<n;i++){
    std::cin>>u[i];
    std::cin>>k[i];
    for(int j=0;j<k[i];j++){
      std::cin>>Adj[i][j];
    }
  }
	
	/*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    	std::cout<<Adj[i][j]<<" ";
    }
  	std::cout<<"\n";
  }*/
	
	v=0;
	firstv=0;
	while(timenow<n*2){
		flag=0;
		if(find[firstv][0]!=NULL&&find[firstv][1]!=NULL){
			for(int i=0;i<n;i++){
				if(find[i][0]==NULL){
					//std::cout<<i<<"\n";
					firstv=i;
					v=i;
					break;
				}
			}
		}
		
		//std::cout<<v+1<<" ";
		///std::cout<<find[v][0]<<" "<<find[v][1];
		
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			//std::cout<<" '"<<timenow<<"' ";
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(endflag[v]==1){
				if(backcount[v]<=1){
				timenow++;
				find[v][1]=timenow;
				//std::cout<<" '"<<timenow<<"' ";
				}
				flag=2;
			}
			//std::cout<<flag<<" 2";
		}else{
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			flag=3;
			//std::cout<<flag<<" 0";
		}

		if(flag==0){
			pred=depth[v];
			depth[v]++;
			prev=v;
			v=Adj[v][pred]-1;
			back[v][backcount[v]]=prev;
			backcount[v]++;
			//std::cout<<flag<<"\n";
		}else if(flag==1){
			if(endflag[v]==0){
				if(Adj[v][depth[v]]-1!=v&&Adj[v][depth[v]]-1!=firstv){
					pred=depth[v];
					depth[v]++;
					prev=v;
					v=Adj[v][pred]-1;
					back[v][backcount[v]]=prev;
					backcount[v]++;
					//std::cout<<v<<"\n";
				}else{
					pred=depth[v];
					depth[v]++;
				}
			}
		}else if(flag==2){
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			//std::cout<<flag<<"\n";
		}
		if(depth[v]>k[v]-1){
			endflag[v]=1;
		}
		
	}
	
	
	
	
  for(int i=0;i<n;i++){
     std::cout<<i+1<<" "<<find[i][0]<<" ";
     std::cout<<find[i][1]<<"\n";
    //std::cout<<"\n";
  }

  return 0;
}

C++: #include<cstdio>
#include<array>
#include<vector>
#include<stack>
using namespace std;
const int MAX_V=101;
array<int,MAX_V> open{0};
array<int,MAX_V> close{0};
array<vector<int>,MAX_V> edge;
int t=0;

void dfs(int f){
  open[f]=++t;
  for(int a:edge[f]){
    if(open[a]==0){
      dfs(a);
    }
  }
  close[f]=++t;
}

int main(){
  int n;scanf("%d",&n);
  for(int i=0;i<n;i++){
    int u;scanf("%d",&u);
    int k;scanf("%d",&k);
    for(int j=0;j<k;j++){
      int v;scanf("%d",&v);
      edge[u].push_back(v);
    }
  }
  for(int i=0;i<n;i++)
    if(open[i+1]==0)
      dfs(i+1);
  for(int i=0;i<n;i++){
    printf("%d %d %d\n",i+1,open[i+1],close[i+1]);
  }
}

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

int A[101][101] = {0};
int n, tt = 0, d[101] = {0}, f[101] = {0}, color[101] = {0};
stack<int> S;

int next(int u) {
    int i;
    for ( i = 1; i <= n; i++ ) {
        if ( A[u][i] == 1 && color[i] != 1 ) return i;
    }

    return -1;
}

void dfs (int u) {
    int i, j ,k;
    S.push(u);
    d[u] = ++tt;
    color[u] = 1;
    while ( !S.empty() ) {
        j = S.top();
        i = next(j);
        if ( i != -1 ) {
            color[i] = 1;
            d[i] = ++tt;
            S.push( i );
        }
    else {
        f[j] = ++tt;
        S.pop();
    }
    }

}

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

    for ( i = 1; i <=n; i++ ) if ( color[i] != 1 ) dfs(i);
    for ( i = 1; i <=n; i++ ) cout << i << ' ' << d[i] << ' ' << f[i] << endl;

    return 0;

}