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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int solve(vector<int>& arr){
  5.     int f_1 = 0;
  6.     int f_2 = 0;
  7.     int f_3 = 0;
  8.     int n = arr.size();
  9.     int c = 0;
  10.     for(int i = 0;i<n;i++){
  11.  
  12.         if(arr[i]==1){
  13.             c+=f_2 + f_3;
  14.         }else if(arr[i]==2){
  15.             c+=f_3;
  16.         }
  17.  
  18.         if(arr[i]==1){
  19.             f_1++;
  20.         }else if(arr[i]==2){
  21.             f_2++;
  22.         }else{
  23.             f_3++;
  24.         }
  25.     }
  26.  
  27.     return c;
  28. }
  29.  
  30. int main() {
  31. 	// your code goes here
  32.     int n;
  33.     cin>>n;
  34.  
  35.     vector<int> arr(n);
  36.     int f_t_1 = 0;
  37.     int f_t_2 = 0;
  38.     int f_t_3 = 0;
  39.     for(int i = 0;i<n;i++){
  40.         cin>>arr[i];
  41.  
  42.         if(arr[i]==1){
  43.             f_t_1++;
  44.         }else if(arr[i]==2){
  45.             f_t_2++;
  46.         }else{
  47.             f_t_3++;
  48.         }
  49.     }
  50.  
  51.  
  52.     int g = solve(arr);
  53.     int ans = g;
  54.     int f1=0,f2=0,f3=0;
  55.     for(int i = 0;i<n;i++){
  56.         if(arr[i]==1){
  57.             int remove_f = g - f2 - f3;
  58.             int turn_2 = remove_f +  f3 + f_t_1-f1 -1;
  59.             int turn_3 = remove_f + f_t_2 - f2 + f_t_1-f1 - 1;
  60.  
  61.             ans = max(ans,max(turn_2,turn_3));
  62.             f1++;
  63.         }else if(arr[i]==2){
  64.             int remove_f = g - f3 - f_t_1 + f1;
  65.             int turn_1 = remove_f + f2 + f3;
  66.             int turn_3 = remove_f + f_t_1 - f1 + f_t_2 - f2;
  67.             ans = max(ans,max(turn_1,turn_3));
  68.             f2++;
  69.         }else{
  70.             int remove_f = g - f_t_1 + f1 - f_t_1 + f1;
  71.             int turn_1 = remove_f + f3 + f2;
  72.             int turn_2 = remove_f + f3 + f_t_1-f1;
  73.             ans = max(ans,max(turn_1,turn_2));
  74.             f3++;
  75.         }
  76.     }
  77.  
  78.     cout<<ans;
  79. }
Success #stdin #stdout 0s 5332KB
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https://ideone.com/ga6aAi
language:
C++14 (gcc 8.3)
created:
24 days ago
visibility:
public

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