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  1. #include <algorithm>
  2. #include <iostream>
  3. using namespace std;
  4.  
  5. int main()
  6. {
  7.     long long n, input, input_back, output = 0;
  8.     long long eel = 0, eel_back = 0;
  9.     long long tuna = 0, tuna_back = 0;
  10.     long long refrence1 = 0, refrence2 = 0;
  11.  
  12.     cin >> n >> input;
  13.     (input == 2 ? ++eel : ++tuna);
  14.  
  15.     for (int i = 1; i < n; ++i)
  16.     {
  17.         input_back = input;
  18.         cin >> input;
  19.  
  20.         if (input != input_back) // then it is an eel  and thew one behind it were a tuna
  21.         {
  22.             if (input == 2)
  23.             {
  24.                 tuna_back = tuna;
  25.                 tuna = 0;
  26.             }
  27.             else
  28.             {
  29.                 eel_back = eel;
  30.                 eel = 0;
  31.             }
  32.         }
  33.  
  34.         if (input == 2)
  35.             ++eel;
  36.         else
  37.             ++tuna;
  38.  
  39.         refrence1 = max(tuna, tuna_back);
  40.         refrence2 = max(tuna, tuna_back);
  41.  
  42.         if (2 * min(refrence1, refrence2) > output)
  43.             output = 2 * min(refrence1, refrence2);
  44.     }
  45.     cout << output;
  46. }
Success #stdin #stdout 0s 5324KB
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4
https://ideone.com/KCxfi5
language:
C++ (gcc 8.3)
created:
1 day ago
visibility:
public

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