Dulce enredo p1, C++ (gcc)

Language: Layout:

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

ll random (int i) 
{ 
    return (rand()%i);
}

ll intervalo(int a, int b)//////////////ints
{
    return rand()%(b-a+1) + a;      //un numero en [a,b]
}

int main () {
  int maxtam = 20;
  int N, K, N_aristas = 0;
    
  srand ( unsigned ( time(0) ) );
  vector<int> myvector;
  stack<int> total;
  vector<vector<int>> graficas;
  vector<stack<int>> stackficas;
  map<int, int> anterior;
  map<int, int> aristas;
  map<int, int> tamanos;
    
  N = intervalo(1,maxtam);
  K = intervalo(1,N);
    
  cout << N << "\n";
  //cout << K << "\n";
    
  graficas.resize(K);
  stackficas.resize(K);
    
  for(int i = 0; i < N; i++)
  {
      graficas[random(K)].push_back(i);
  }

for(auto a: graficas)
      random_shuffle ( a.begin(), a.end() );
  
  //random_shuffle ( myvector.begin(), myvector.end() );

for(int i = 0; i < K; i++)
      tamanos[i] = graficas[i].size();
    
  /*for(auto a: tamanos)
      cout << a.first << " " << a.second << "\n";*/

for(int i = 0; i < K; i++)
  {
     int n = tamanos[i];
     if(n > 0)
         aristas[i] = n-1; 
  }
  
  for(int i = 0; i < K; i++)
  {
      for(int j = 0; j < graficas[i].size(); j++)
          stackficas[i].push(graficas[i][j]);
  }
    
  /*for(auto a: stackficas)
  {
      cout << "Grafica: \n";
      while(!a.empty())
      {
          cout << a.top() << "\n";
          a.pop();
      }
  }*/
    
  for(auto a: aristas)
  {
      N_aristas+=a.second;
  }
    
  cout << N_aristas << "\n";
    
  for(int i = 0; i < K; i++)
  {
     int n = aristas[i];
     int anterior;
     //cout << "Aristas: \n";
     while(!stackficas[i].empty() and stackficas[i].size() > 1)
     {
         cout << stackficas[i].top() << " ";
         stackficas[i].pop();
         cout << stackficas[i].top() << "\n";
     }
  }
    
  cout << '\n';

return 0;
}

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Compilation time: 1.83 sec, absolute running time: 0.07 sec, cpu time: 0.01 sec, memory peak: 3 Mb, absolute service time: 1,91 sec