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<algorithm>
using namespace std;

int n;
int t = 0; //time
int d[110] = {}; //discover
int f[110]; //finish
bool a[110][110] = {}; //adjacency matrix

void dfs(int u){
  d[u] = ++t; //record the discovering time

  //if be adjoining and have not been discovered, search
  for(int i = 1;i <= n;i++) if(a[u][i] && d[i] == 0) dfs(i);
  
  f[u] = ++t; //record the finishing time
}

int main(){
  
  int u, k, v;

  //input
  cin >> n;
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> v;
      a[u][v] = true;
    }
  }

  for(int i = 1;i <= n;i++){
    for(int j = 1;j <= n;j++){
      //if be adjoining and have not been discovered, search
      if(a[i][j] && d[i] == 0) dfs(i);
    }
  }

  //output
  for(int i = 1;i <= n;i++) cout << i << " " << d[i] << " " << f[i] << endl;
  
  return 0;
}

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

class Graph {
protected:
	vector< vector<int> > adjl;
public:
	Graph(int n) : adjl(n){}
	void PushAdjl(int pl, int val) { adjl[pl].push_back(val); }
};

class DFGraph : public Graph {
private:
	int t;
	vector<int> d, f;
public:
	DFGraph(int n) : Graph(n), d(n), f(n) {}
	void DepthFirstSearch(int);
	void DFSSub(int);
	void Showdf();
};

void DFGraph::DepthFirstSearch(int begin = 0) {
	t = 1;
	DFSSub(begin);
	for (int i = 0; i < d.size(); i++)
		if (d[i] == 0)
			DFSSub(i);
}

void DFGraph::DFSSub(int v) {
	d[v] = t;
	t++;
	for (auto&& i : adjl[v])
		if (d[i] == 0)
			DFSSub(i);
	f[v] = t;
	t++;
}

void DFGraph::Showdf() {
	for (int i = 0; i < d.size(); i++)
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
}

int main() {
	int n;
	cin >> n;
	DFGraph dfg(n);
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int t;
			cin >> t;
			dfg.PushAdjl(u - 1, t - 1);
		}
	}
	dfg.DepthFirstSearch();
	dfg.Showdf();
}

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

int m[101][101];
int visit[101];
int d[101];
int f[101];
int n, t;

void dfs(int u){
  visit[u] = 1;
  d[u] = t;
  t++;
  
  for(int i = 0; i < n; ++i){
    if(m[u][i] == 1 && visit[i] == 0){
      dfs(i);
    }
  }

  f[u] = t;
  t++;
}

main()
{
  int u, k, v;
  
  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;
    }
  }

  for(int i = 0; i < n; ++i){
    if(visit[i]==0){
      t=1;
      dfs(i);
    }
  }

  for(int i=0; i < n; ++i){
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }

  return (0);
}

C++: #include <iostream>
#include<stack>
#include<vector>
using namespace std;
int main(void){
    int n ,i,DP[1001][1001],num,p,k,f[101][3],ptr=1,v;
    stack<int> s;
        cin>>n;
    for(i=1;i<=n;i++){
        cin>>p>>k;
        for(int j=1;j<=k;j++){
            cin>> num;
            DP[i][num]=1;
        }
    }
    for(i=1;i<=n;i++){
        DP[0][i]=1;
    }
    s.push(0);
    while(!s.empty()){
        v=s.top();
        for(int i=1;i<=n;i++){
            if(DP[v][i]==1&&f[i][0]==0){
                    s.push(i);
                    f[i][0]=1;
                    f[i][1]=ptr;
                    goto Exit;
            }
        }
        s.pop();
        f[v][2]=ptr;
        Exit:;
        ptr++;
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<f[i+1][1]<<" "<<f[i+1][2]<<endl;
    }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int n;
int t;
vector< vector<int> > A;
vector<int> c;
vector<int> d;
vector<int> f;

void dfsVisit(int u) {
    t++;
    d[u] = t;
    c[u] = 1;
    for(int i=0; i<A[u].size(); i++) {
        int v = A[u][i];
        if(c[v] == 0) dfsVisit(v);
    }
    t++;
    f[u] = t;
}

void dfs() {
    for(int u=0; u<n; u++) c[u] = 0;
    t = 0;
    for(int u=0; u<n; u++) {
        if(c[u] == 0) {
            dfsVisit(u);
        }
    }
}

int main() {
    cin >> n;
    A.resize(n);
    c.resize(n);
    d.resize(n);
    f.resize(n);

    for(int i=0; i<n; i++) {
        int u,k;
        cin >> u >> k;
        A[u-1].resize(k);
        for(int j=0; j<k; j++) {
            int v;
            cin >> v;
            A[u-1][j] = v-1;
        }
        sort(A[u-1].begin(), A[u-1].end());
    }

    dfs();
    for(int i=0; i<n; i++) cout << i+1 << " " << d[i] << " " << f[i] << endl;
}

C++: #include <iostream>

using namespace std;

int adja[101][101];
int d[101], f[101], cnt;

void dfs(int u) {
    d[u] = ++cnt;
    for (int i = 0, v; (v = adja[u][i]) > 0; ++i) {
        if (v > 0)
            continue;
        dfs(v);
    }
    f[u] = ++cnt;
}

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

    return 0;
}

C++: #include <bits/stdc++.h>
#define REP(i,n) for (int i=0;i<(n);i++)
#define All(v) (v).begin(),(v).end()
#define mp(a,b) make_pair(a,b)
#define pb(a) push_back(a)
using namespace std;
typedef long long llint;
typedef pair<int, int> P;
const int MOD = (int)1e9 + 7;
const int INF = 999999999;

int N;
int tt = 0;
vector< vector<int> > G;
vector<int> H, d, f;
int itrNum[100001];
stack<int> S;

void dfs(int u){
    S.push(u);
    H[u] = 0;

    while(!S.empty()){
        u = S.top();  // ?¨????????????????
        if(d[u] == 0) d[u] = ++tt;
        auto itr_v = next(G[u].begin(), itrNum[u]);
        if(itr_v != G[u].end()){
            itrNum[u]++;
            int v = *itr_v;
            if(H[v] == -1){
                H[v] = 0;
                S.push(v);
            }
        }else{
            S.pop();
            H[u] = 1;
            f[u] = ++tt;
        }
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> N;
    G = vector<vector<int> >(N);
    H = vector<int>(N, -1);
    d = vector<int>(N, 0);
    f = vector<int>(N, 0);
    memset(itrNum, 0, sizeof(itrNum));
    REP(i, N){
        int u,k;
        cin >> u >> k;
        u--;
        REP(j ,k){
            int v;
            cin >> v;
            v--;
            G[u].pb(v);
        }
    }

    REP(i, N) if(H[i] == -1) dfs(i);
    REP(i, N){
        cout << i+1 << " " << d[i] << " " << f[i] << "\n";
    }
    return 0;
}