func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2410;   int n, l, r, a[N];   vector<int> p;   tuple<int, int, int> tmp[2];   vector<tuple<int, int, int>> ans;   int main() {     ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);     cin >> n;     for (int i = 1, x; i <= 3 * n; i++) cin >> x, a[x] = 1;     for (int i = 1; i <= 6 * n; i++) p.push_back(i);     for (int i = 1; i <= 2 * n; i++) {       l = 0, r = p.size() - 1;       while (l < r && a[p[l]] == a[p[l + 1]] && a[p[l]] == a[p[l + 2]])         tmp[a[p[l]]] = {p[l], p[l + 1], p[l + 2]}, l += 3;       while (l < r && a[p[r]] == a[p[r - 1]] && a[p[r]] == a[p[r - 2]])         tmp[a[p[r]]] = {p[r - 2], p[r - 1], p[r]}, r -= 3;       if (l < r) {         for (int j = l; j + 2 <= r; j++)           if ((i & 1) == a[p[j]] && (i & 1) == a[p[j + 1]] &&               (i & 1) == a[p[j + 2]]) {             ans.push_back({p[j], p[j + 1], p[j + 2]});             goto next;           }       }       ans.push_back(tmp[i & 1]);     next:       p.erase(find(p.begin(), p.end(), get<0>(ans.back())));       p.erase(find(p.begin(), p.end(), get<1>(ans.back())));       p.erase(find(p.begin(), p.end(), get<2>(ans.back())));     }     for (const auto &it : ans)       cout << get<0>(it) <<     << get<1>(it) <<     << get<2>(it) << endl;   }   