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<stdio.h>
#define MAX 100

int adj[MAX][MAX];/*隣接行列*/
int d[MAX];/*発見時刻*/
int f[MAX];/*終了時刻*/
int flg[MAX];/*ノード訪問したかどうか*/
int time=0;

void dfs(int u,int n){
	
	flg[u]=1;
	d[u]=++time;
	
	for(int i=0;i<n;i++){
		if(adj[u][i] && !flg[i]){/*ノードuから到達可能かつ未訪問*/
			dfs(i,n);
		}
	}
	f[u]=++time;
	
	return;
	
}

int main(){
	int n,i,j;
	int x,y,z;
	
	scanf("%d",&n);
	
	for(i=0;i<n;i++){
		flg[i]=0;
		for(j=0;j<n;j++)
			adj[i][j]=0;
	}
	
	for(i=0;i<n;i++){
		scanf("%d %d",&x,&y);
		for(j=0;j<y;j++){
			scanf("%d",&z);
			adj[x-1][z-1]=1;
		}
	}
	
	for(i=0;i<n;i++)
		if(!flg[i])
			dfs(i,n);
	
	
	for(i=0;i<n;i++)
		printf("%d %d %d\n",i+1,d[i],f[i]);
	
	return 0;
	
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <algorithm>
#include <array>
#include <stack>
#include <map>

using namespace std;

template<typename ISTREAM>
void readGraphListAsMatrix(const size_t n, ISTREAM& cin, vector< vector<int> >& graphMatrix) {
	graphMatrix = vector< vector<int> >(n, vector<int>(n, 0));
	for (size_t i = 0; i != n; ++i) {
		size_t u;
		size_t k;
		cin >> u;
		cin>> k;
		for (size_t j = 0; j != k; ++j) {
			size_t v;
			cin >> v;
			graphMatrix.at(u - 1).at(v - 1) = 1;
		}
	}
}

void printMatrix(const vector< vector<int> >& grapthMatrix) {
	const size_t n = grapthMatrix.size();
	for (size_t i = 0; i != n; ++i) {
		const vector<int>& adj = grapthMatrix.at(i);
		cout << adj.front();
		for (size_t j = 1; j != n; ++j) {
			cout << " " << adj.at(j);
		}
		cout << endl;
	}
}


template<typename T>
void execute(T& cin) {
	size_t n;
	cin >> n;
	vector< vector<int> > graphMatrix;
	readGraphListAsMatrix(n, cin, graphMatrix);
	stack<int> visitedNodeIDs;
	visitedNodeIDs.push(0);
	int time = 0;
	vector<pair<int, int>> timeStamp(n,make_pair(0,0));//pair<初回訪問時刻, 完了時刻>
	vector<vector<int>::iterator> searchBeginPos; {
		searchBeginPos.reserve(n);
		for (auto& v : graphMatrix)searchBeginPos.push_back(v.begin());
	}
	timeStamp.at(0).first = 1;
	while (!visitedNodeIDs.empty()) {
		++time;
		const int nodeID_1 = visitedNodeIDs.top();
		vector<int>& neighbourNodeList = graphMatrix.at(nodeID_1);
		vector<int>::iterator result = find(searchBeginPos.at(nodeID_1), neighbourNodeList.end(), 1);
		if (result != neighbourNodeList.end()) {
			const int nextVisitID_1 = distance(neighbourNodeList.begin(), result);
			timeStamp.at(nextVisitID_1).first = time + 1;
			for (auto&v : graphMatrix) v.at(nextVisitID_1) = 0;
			visitedNodeIDs.push(nextVisitID_1);
			searchBeginPos.at(nodeID_1) = result + 1;
		}
		else {
			//隣接リストに検索対象なし
			timeStamp.at(nodeID_1).second = time+1;
			visitedNodeIDs.pop();
		}
	}
	for (int i = 0; i != n; ++i) {
		cout << i + 1 << " " << timeStamp.at(i).first << " " << timeStamp.at(i).second << endl;
	}
}

int main()
{
	execute(cin);

	return 0;
}

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

int d[101]={0};
int f[101]={0};
int AdjM[101][101]={0};
int lapse=0;

void dfs(int cur){
    ++lapse;
    d[cur]=lapse;
    //cerr<<"visiting "<<cur<<" "<<lapse<<"\n";
    for(int dst=1;dst<101;++dst){
        if(AdjM[cur][dst]!=0 && d[dst]==0){
            dfs(dst);
        }
    }
    ++lapse;
    f[cur]=lapse;
}

int main(){
    int N;
    cin>>N;
    int id,edgnum,adj;
    for(int i=0;i<N;++i){
        cin>>id>>edgnum;
        for(int j=0;j<edgnum;++j){
            cin>>adj;
            AdjM[id][adj]+=1;
        }
    }

    for(int i=1;i<=N;++i){
        if(d[i]==0){
            dfs(i);
        }
    }

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

C++: #include <iostream>
#include <stack>
#define NUM 100
using namespace std;
int process_time;

typedef enum
{
    PRE,
    NOW,
} NodeStatus;

struct Node
{
    int num;
    int *p;
    int d;
    int f;

    int status;
    void Set(int num);
};

void Node::Set(int n)
{
    this->num = n;
    this->status = PRE;
    p = new int[n];
    for (int i = 0; i < n; i++)
    {
        cin >> p[i];
    }
}

void Search(Node *vertex, int start)
{
    stack<Node *> st;

    st.push(&vertex[start]);
    vertex[start].status = NOW;
    vertex[start].d = process_time;
    while (!st.empty())
    {
        process_time++;
        int k = st.top()->num;
        int i;
        for (i = 0; i < k; i++)
        {
            if (vertex[st.top()->p[i]].status == PRE)
            {
                break;
            }
        }
        if (i == k)
        {
            Node *v;
            v = st.top();
            st.pop();
            v->f = process_time;
        }
        else
        {
            st.push(&vertex[st.top()->p[i]]);
            st.top()->d = process_time;
            st.top()->status = NOW;
        }
    }
}

int main()
{
    int n;
    Node vertex[NUM];
    cin >> n;

    for (int i = 0; i < n; i++)
    {
        int k, u;
        cin >> u >> k;
        vertex[u].Set(k);
    }

    process_time = 1;
    Search(vertex, 1);

    int count;
    for (count = 1; count <= n; count++)
    {
        if (vertex[count].status == PRE)
        {
            break;
        }
    }
    if (count != n + 1)
    {
        process_time++;
        Search(vertex, count);
    }

    for (int i = 1; i <= n; i++)
    {
        cout << i << ' ' << vertex[i].d << ' ' << vertex[i].f << endl;
    }
    /*for (int i = 1; i <= n; i++) //1オリジン
    {
        for (int j = 0; j < vertex[i].num; j++)
        {
            cout << vertex[i].p[j] << ' ';
        }
        cout << endl;
    }*/

    return 0;
}