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 <set>
#include <vector>
#include <queue>
#include <stack>
#include <utility>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

int g[101][101],n,d[101],f[101];

int main() {
    cin >> n;
    for(int i = 0;i < n;i++) {
        int u,k,v;
        cin >> u >> k;
        for(int j = 0;j < k;j++) {
            cin >> v;
            g[u][v]++;
        }
    }
    stack<int> dfs;
    int time = 2;
    dfs.push(1);
    d[1] = 1;
    bool flag = true;
    while(flag) {
        while (!dfs.empty()) {
            int u = dfs.top();
            bool fl = false;
            for (int i = 1; i <= n; i++) {
                if (g[u][i] && d[i] == 0 && u != i) {
                    dfs.push(i);
                    d[i] = time++;
                    fl = true;
                    break;
                }
            }
            if (!fl) {
                dfs.pop();
                f[u] = time++;
            }
        }
        flag = false;
        for(int i =1;i <= n;i++) if(d[i] == 0){flag = true;dfs.push(i);d[i] = time++;break;}
    }
    for(int i = 1;i <=n;i++) {
        cout << i << " " << d[i] << " " << f[i] <<endl;
    }
}

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){
	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;
	d[0] = t;
	dfs(0, d, f, a);

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

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())

ll n, t = 0;
vector<vector<ll>> g;
vector<ll> d, f;

void dfs(ll v, ll p = -1) {
    if (d[v] != -1) return;
    t++;
    d[v] = t;
    rep(i, sz(g[v])) {
        if (g[v][i] == p) continue;
        dfs(g[v][i], v);
    }
    f[v] = t;
    t++;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    cin >> n;
    g.resize(n);
    rep(i, n) {
        ll u, k;
        cin >> u >> k;
        u--;
        rep(j, k) {
            ll v;
            cin >> v;
            v--;
            g[u].push_back(v);
        }
    }
    rep(i, n) sort(all(g[i]));
    d.resize(n, -1);
    f.resize(n, -1);
    rep(i, n) {
        if (d[i] == -1) dfs(i);
    }
    rep(i, n) {
        printf("%lld %lld %lld\n", i + 1, d[i], f[i] + 1);
    }
    return 0;
}

C++: #if 0
????????£?????????????´??????????
?????°?????¨??????dfs??????????????????????°??????§?????????
#endif

#include <iostream>
#include <vector>
using namespace std;
vector<int> E[101];
bool visited[101];
int in[101];
int out[101];
int count=0;
int nv(int n)
{
    int i=1;
    for(i=1;i<=n;i++)
    {
        if ( visited[i]==false )
            return i;
    }
    if (i>n) return 0;
}

void dfs(int n)
{
    visited[n]=true;
    in[n]=++count;
    for(vector<int>::iterator it=E[n].begin();it!=E[n].end();++it)
    {
        int now=*it;
        if(visited[now]==false)
            dfs(now);
    }
    out[n]=++count;
}

int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        int e,n0;
        cin>>e>>n0;
        for(int j=0;j<n0;j++)
        {
            int t;
            cin>>t;
            E[e].push_back(t);
        }
        visited[i]=false;
        in[i]=out[i]=0;
    }

    int now=nv(n);
    while(now!=0)
    {
        dfs(now);
        now=nv(n);
    }


/*  for(int i=1;i<=n;i++)
    {
        for(vector<int>::iterator it=E[i].begin();it!=E[i].end();++it)
            cout<<*it<<" ";
        cout<<endl;
    }
*/
    for(int i=1;i<=n;i++)
        cout<<i<<" "<<in[i]<<" "<<out[i]<<endl;
    return 0;



}

C++: #include <iostream>

using namespace std;

	int TIME = 0;
	int d[101];
	int f[101];
	int num;
	int graph[101][101] = {0};

void dfs(int x){
	TIME++;
	d[x] = TIME;

	for(int i=1;i<=num;i++){
		if(graph[x][i] == 1 && d[i]==0){
			dfs(i);
		}
	}
	f[x] = ++TIME;
}

int main(){
	int hon;
	int eda;
	int ver;

	cin>>num;
	for(int i=0;i<num;i++){
		cin>>eda;
		cin>>hon;
		for(int j=0;j<hon;j++){
			cin>>ver;
			graph[eda][ver]++;
		}
	}

	dfs(1);

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

	return 0;
}

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

int n;
vector<vector<int> > A;
vector<vector<int> > T;
int time = 0;

void dfs(int cur){ // cur????¨????
    // cur ????¨??????????????¨????
    time += 1;
    T[cur][0] = time;
    // ???????¢??????¨??¨???
    cerr << "visiting " << cur << " " << time << endl;

    for(int dst = 0; dst < n; ++dst){ // ??¨???????????? dst ????????????
        if(A[cur][dst] == 1 && T[dst][0] == -1){ // cur??????dst??????????????????,dst???????¨??????????
            dfs(dst);
        }
    }
    // cur ????¨????????????????????¨????
    time += 1;
    T[cur][1] = time;
    // ??¢??°?????????????????????????????? (?????¢??°)
    return; // ?????\???
}

int main(){
    cin >> n;
    vector<vector<int> > A(n, vector<int>(n, 0));
    vector<vector<int> > T(n, vector<int>(2, -1));
    for(int i=0; i<n; ++i){
        int k;
        cin >> k;
        // 1~n???index?????¨????????????????????????????????????1????????????0~n-1????????????
        k -= 1;
        int u;
        cin >> u;
        for(int j=0; j<u; ++j){
            int v;
            cin >> v;
            v -= 1;
            A[k][v] = 1;
        }
    }
    for(int i=0; i<n; ++i){
        if(T[i][0] == -1){
          dfs(i);
        }
    }
    for(int i=0; i<n; ++i){
        cout << i+1 << T[i][0] << T[i][1] << endl;
    }
}