Go: #include <bits/stdc++.h>
using namespace std;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int N     = 100;

int n, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

void dfs_visit(int u) {
  color[u] = GRAY;
  d[u]     = ++tt;
  for (int v = 0; v < n; v++) {
    if (M[u][v] == 0) continue;
    if (color[v] == WHITE) { dfs_visit(v); }
  }
  color[u] = BLACK;
  f[u]     = ++tt;
}

void dfs() {
  tt = 0;

  for (int u = 0; u < n; u++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int u = 0; u < n; u++) {
    printf("%d %d %d\n", u + 1, d[u], f[u]);
  }
}

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

  dfs();
}

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

using namespace std;

template <class T>
struct Edge {
    int to;
    T cost;
    Edge(int to, T cost) : to(to), cost(cost){};
};

template <class T = int>
class Graph {
public:
    explicit Graph(int N = 0) : size(N) { path.resize(size); }
    void span(int u, int v, T cost = 1) { path[u].push_back(Edge<T>(v, cost)); }
    vector<Edge<T>> operator[](int v) const { return path[v]; }

    int size;
    vector<vector<Edge<T>>> path;
};

int main() {
    int N;
    cin >> N;
    Graph<> graph(N);
    for (int i = 0; i < N; ++i) {
        int v, k;
        cin >> v >> k;
        --v;
        for (int j = 0; j < k; ++j) {
            int sv;
            cin >> sv;
            graph.span(v, --sv);
        }
    }

    vector<int> d(N, -1), f(N, -1);
    function<int(int, int)> dfs = [&](int v, int t) -> int {
        d[v] = t;
        for (auto e : graph[v]) {
            if (d[e.to] < 0) t = dfs(e.to, t + 1);
        }
        return f[v] = ++t;
    };

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

    for (int v = 0; v < N; ++v) {
        cout << v + 1 << " " << d[v] << " " << f[v] << endl;
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,a) for(int i=0;i<a;i++)
#define pd(a,n) for(int i=0;i<n;i++)cout<<a[i]<<((i==n-1)?"\n":" ")
#define pdd(a,n,m)for(int i=0;i<m;i++)pd(a,m)
#define mp make_pair
#define pb push_back
#define ll __int64
#define __int64 long long
#define P pair<int,int>
#define PP pair<P,int>

int n;
vector<int>G[1111];
int d[111];
int f[111];
int cnt;

void dfs(int x){

  d[x]=++cnt;

  rep(i,G[x].size()){
    int to=G[x][i];
    if(d[to]==0)
      dfs(to);
  }
  f[x]=++cnt;
}

int main(){
  cin>>n;
  rep(i,n){
    int k,s;
    cin>>k>>s;
    rep(j,s){
      int to;
      cin>>to;
      G[k].pb(to);
    }
    sort(G[k].begin(),G[k].end());
  }

  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]<<endl;
  }

  return 0;
}

C++: #include <iostream>
using namespace std;
int t = 1;
int d[100], f[100];
int a[100][100];
int N;
void dfs(int cur) {
 d[cur] = t;
 t++;
 for (int i=0; i<N; i++) {
  if (a[cur][i] == 1 && d[i] == 0) {
   dfs(i);
  }
 }
 f[cur] = t;
 t++;
}

int main() {
 cin >> N;
 for (int i=0; i<N; i++) {
  for (int j=0; j<N; j++) {
   a[i][j] = 0;
  }
  d[i] = 0;
  f[i] = 0;
 }
 for (int i=0; i<N; i++) {
  int u, k;
  cin >> u >> k;
  for (int j=0; j<k; j++) {
   int v;
   cin >> v;
   a[u-1][v-1] = 1;
  }
 }
 for (int i=0; i<N; i++) {
  if (d[i] == 0) { dfs(i); }
 }
 for (int i=0; i<N; i++) {
  cout << i+1 << " " << d[i] << " " << f[i] << endl;
 }
}

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

struct TNode
{
	int Index;
	bool Visited;
	std::list<TNode*> Target;
	
	int ClockStart;
	int ClockEnd;
	
	TNode(int AIndex)
	: Index(AIndex), Visited(false), ClockStart(0), ClockEnd(0)
	{
	}
	
	void Visit(int& Clock)
	{
		if(Visited) return;
		Visited = true;
		ClockStart = Clock;
		++Clock;
		for(std::list<TNode*>::iterator It = Target.begin(); It != Target.end(); ++It){
			(*It)->Visit(Clock);
		}
		ClockEnd = Clock;
		++Clock;
	}
};

class TGraph
{
	std::vector<TNode*> FNodes;
public:
	TGraph(int Count)
	: FNodes(Count)
	{
		for(int i = 0; i < Count; ++i){
			FNodes[i] = new TNode(i + 1);
		}
	}
	
	~TGraph()
	{
		for(unsigned int i = 0; i < FNodes.size(); ++i){
			delete FNodes[i];
		}
	}
	
	void InputNode(int Index, int BranchCount)
	{
		for(int i = 0; i < BranchCount; ++i){
			int Target;
			std::cin >> Target;
			FNodes[Index - 1]->Target.push_back(FNodes[Target - 1]);
		}
	}
	
	void DepthFirstSearch()
	{
		int Clock = 1;
		FNodes[0]->Visit(Clock);
	}
	
	void OutputClocks()const
	{
		for(unsigned int i = 0; i < FNodes.size(); ++i){
			std::cout << FNodes[i]->Index      << " "
			          << FNodes[i]->ClockStart << " "
			          << FNodes[i]->ClockEnd   << std::endl;
		}
	}
};

int main()
{
	int Count;
	std::cin >> Count;
	TGraph Graph(Count);
	for(int i = 0; i < Count; ++i){
		int Index;
		std::cin >> Index;
		int BranchCount;
		std::cin >> BranchCount;
		Graph.InputNode(Index, BranchCount);
	}
	Graph.DepthFirstSearch();
	Graph.OutputClocks();
	return 0;
}

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

using namespace std;

int n;
vector<vector<int>> g; 
int time = 0;
vector<int> d, f;
 
void dfs(int node){
    time++;

    if(d[node] == 0){
        d[node] = time;
    }

    for(auto next : g[node]){
        if(d[next] == 0){
            dfs(next);
        }
    }
    
    time++;
    if(f[node] == 0){
        f[node] = time;
    }
}
    
int main(){
    
    cin >> n;

    d.assign(n + 1, 0);
    f.assign(n + 1, 0);

    g.assign(n + 1, vector<int>());

    for(int i = 0; i < n; i++)
    {
        int nod, numOut;
        cin  >> nod >> numOut;
        for(int j = 0; j < numOut; j++)
        {
            int temp;
            cin >> temp;
            g[nod].push_back(temp);
        }
    }
    
    dfs(1);

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

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
constexpr int di[] = {0, 1, 0, -1}, dj[] = {1, 0, -1, 0};
#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define sort(v) sort((v).begin(), (v).end())
#define sortr(v) sort((v).rbegin(), (v).rend())
#define all(v) (v).begin(), (v).end()
#define max 100005
#define nil -1

vector<vector<int>> g;
int t=0;
vector<int> d,f;
vector<bool> visited;

void dfs(int u){
    visited[u]=true;
    t++;
    d[u]=t;
    for(auto to:g[u]){
        if(!visited[to]){
            dfs(to);
        }
    }
    t++;
    f[u]=t;
}

int main() {
  int  n,u,k,v;
  cin>>n;
    g.resize(n);
    d.resize(n);
    f.resize(n);
    visited.resize(n, false);
  rep(i,n){
      cin>>u>>k;
      u--;
      for(int j=0;j<k;j++){
          cin>>v;
          v--;
          g[u].push_back(v);
        }
    }
    rep(i,n){
        if(!visited[i]){
            dfs(i);
        }
    }
    rep(i,n){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
  return 0;
}