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 <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;
#define MAX 101

int n;
Graph G(MAX);
vector<bool> seen(MAX, false);
vector<int> d(MAX), f(MAX);
int timer = 1;

void dfs(const Graph &G, int v)
{
  seen.at(v) = true;
  d.at(v) = timer++;
  int next_v;
  for (int i = 0; i < G.at(v).size(); i++)
  {
    next_v = G.at(v).at(i);
    if (seen.at(next_v))
    {
      continue;
    }
    dfs(G, next_v);
  }
  f.at(v) = timer++;
}

int main()
{
  cin >> n;
  int k, u, v;
  for (int i = 0; i < n; i++)
  {
    cin >> u >> k;
    for (int j = 0; j < k; j++)
    {
      cin >> v;
      G.at(u).push_back(v);
    }
  }
  for (int v = 1; v <= n; v++)
  {
    if (seen.at(v))
    {
      continue;
    }
    dfs(G, v);
  }
  for (int i = 1; i <= n; i++)
  {
    cout << i << " " << d.at(i) << " " << f.at(i) << endl;
  }
}

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

using namespace std;

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

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

    for(auto next : g[node]){
        if(d[next] == 0){
            dfs(next);
        }
    }
    
    timeT++;
    if(f[node] == 0){
        f[node] = timeT;
    }
    return;
}
    
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);
        }
    }
    
    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<bits/stdc++.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) for(int i = 0; i < (b); i++)
#define all(a) (a).begin(), (a).end()
#define show(x)  cerr << #x << " = " << (x) << endl;
//const int INF = 1e8;
using namespace std;

int t;

void dfs(int pos, vector<int>& d, vector<int>& f, vector<vector<int>>& a){
	d[pos] = t;
	rep(i,a.size()){
		if(a[pos][i] == 1 and d[i] == -1){
			t++;
			d[i] = t;
			dfs(i, d, f, a);
		}
	}
	t++;
	f[pos] = t;
}

int main(){
	int n;
	cin >> n;

	vector<vector<int>> a(n, vector<int>(n,0));
	rep(i,n){
		int from;
		int m;
		cin >> from >> m;
		from--;
		rep(j,m){
			int to;
			cin >> to;
			to--;
			a[from][to] = 1;
		}
	}

	vector<int> d(n,-1), f(n);
	t = 1;
	rep(i,n){
		if(d[i] == -1) {
			dfs(i, d, f, a);
			t++;
		}
	}

	rep(i,n){
		cout << i + 1 << ' ' << d[i] << ' ' << f[i] << endl;
	}
}

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;
    }
    return;
}
    
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 <iostream>
#include <stack>
using namespace std;
const int MAX_N = 100;

int A[MAX_N+1][MAX_N+1];
pair<int, int> TIMESTAMPS[MAX_N+1];
int N;

void solve() {
  int ts = 0;
  stack<int> S;

  for (int i = N; i > 0; i--) {
    if (TIMESTAMPS[i].first == 0) S.push(i);
  }

  while (!S.empty()) {
    int c = S.top();

    if (TIMESTAMPS[c].first == 0)
      TIMESTAMPS[c].first = ++ts;

    for (int i = N; i > 0; i--) {
      if (A[c][i] == 1 && TIMESTAMPS[i].first == 0)
        S.push(i);
    }

    if (S.top() == c) {
      if (TIMESTAMPS[c].second == 0)
        TIMESTAMPS[c].second = ++ts;
      S.pop();
    }
  }
}

int main() {
  cin >> N;

  for (int i = 1; i <= N; i++) {
    for (int j = 1; j <= N; j++) {
      A[i][j] = 0;

    }
    TIMESTAMPS[i] = make_pair(0, 0);
  }

  for (int i = 0; i < N; i++) {
    int u, k; cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int t; cin >> t;
      A[u][t] = 1;
    }
  }

  solve();

  for (int i = 1; i <= N; i++) {
    cout << i << ' '
         << TIMESTAMPS[i].first << ' '
         << TIMESTAMPS[i].second << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#define rep(i, n) for(int i = 0; i < (int)(n); ++i)
#define REP(i, n) for(int i = 1; i < (int)(n); ++i)
using namespace std;

int n;
vector<vector<int>> graph(100);
vector<int> d(100, 0), f(100);
int t = 0;

void DFS(int u) {
    if (d[u] != 0) return;
    ++t;
    d[u] = t;
    for (int v : graph[u]) DFS(v);
    ++t;
    f[u] = t;
    return;
}

int main() {
    cin >> n;
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(j, k) {
            int v;
            cin >> v;
            graph[u - 1].push_back(v - 1);
        }
    }
    
    rep(i, n) DFS(i);
    rep(i, n) cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    return 0;
}

C++: /* ALDS1_11_B: Depth First Search */

#include <iostream>
#include <cstdio>
#include <vector>
using std::vector;

vector<int> *graph;
int elapsed = 1;

// Search the graph recursively by depth-first search.
void traverse(int id, int found[], int finished[]) {
    if (0 < found[id]) {
        return;
    }

    found[id] = elapsed++;
    vector<int> degrees = graph[id];
    for (int i = 0; i < degrees.size(); i++) {
        traverse(degrees[i], found, finished);
    }
    finished[id] = elapsed++;
}

int main() {
    int n_v;
    scanf("%d", &n_v);

    int max_v = n_v + 1;
    graph = new vector<int>[max_v];

    for (int i = 0; i < max_v; i++) {
        int id, n_degrees;
        scanf("%d %d", &id, &n_degrees);

        for (int j = 0; j < n_degrees; j++) {
            int deg_id;
            scanf("%d", &deg_id);
            graph[id].push_back(deg_id);
        }
    }

    int found[max_v];
    int finished[max_v];
    std::fill_n(found, max_v, 0);
    std::fill_n(finished, max_v, 0);

    for (int id = 1; id < max_v; id++) {
        traverse(id, found, finished);
    }

    for (int id = 1; id < max_v; id++) {
        printf("%d %d %d\n", id, found[id], finished[id]);
    }
    return 0;
}