Problem:
Score : 300 points

Problem Statement

A sequence a_1,a_2,... ,a_n is said to be /\/\/\/ when the following conditions are satisfied:

For each i = 1,2,..., n-2, a_i = a_{i+2}.

Exactly two different numbers appear in the sequence.

You are given a sequence v_1,v_2,...,v_n whose length is even.
We would like to make this sequence /\/\/\/ by replacing some of its elements.
Find the minimum number of elements that needs to be replaced.

Constraints

2 \leq n \leq 10^5

n is even.

1 \leq v_i \leq 10^5

v_i is an integer.

Input

Input is given from Standard Input in the following format:

n
v_1 v_2 ... v_n

Output

Print the minimum number of elements that needs to be replaced.

Sample Input 1

4
3 1 3 2

Sample Output 1

1

The sequence 3,1,3,2 is not /\/\/\/, but we can make it /\/\/\/ by replacing one of its elements: for example, replace the fourth element to make it 3,1,3,1.

Sample Input 2

6
105 119 105 119 105 119

Sample Output 2

0

The sequence 105,119,105,119,105,119 is /\/\/\/.

Sample Input 3

4
1 1 1 1

Sample Output 3

2

The elements of the sequence 1,1,1,1 are all the same, so it is not /\/\/\/.

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include "iostream"
#include "algorithm"
#include "vector"
#include "string"
#include "cmath"
#include <map>

int main(int argc, char const *argv[]) {

  // int maxx = 1e5;
  // int c0[maxx], c1[maxx];
  // for (size_t i = 0; i < 1e5; i++) {
  //   c0[i] = 0;
  //   c1[i] = 0;
  // }

  std::map<int,int> c0{};
  std::map<int,int> c1{};


  int N;
  std::cin >> N;



  for (size_t i = 0; i < N; i++) {
    int v;
    std::cin >> v;
    if (i%2 == 0) {
      c0[v] += 1;
    }else{
      c1[v] += 1;
    }
  }

  int c0max = 0, c1max = 0;
  int c0smax = 0, c1smax = 0;
  int v0 = 0, v1 = 0;

  for (std::map<int,int>::iterator it=c0.begin(); it!=c0.end(); ++it){
        if(it->second >= c0max){
          c0smax = c0max;
          c0max = it->second;
          v0 = (it->first);
        }else{
          if (it->second > c0smax) {
            c0smax = it->second;
          }
        }
  }

  for (std::map<int,int>::iterator it=c1.begin(); it!=c1.end(); ++it){
        if(it->second >= c1max){
          c1smax = c1max;
          c1max = it->second;
          v1 = (it->first);

        }else{
          if (it->second > c1smax) {
            c1smax = it->second;
          }
        }
  }

  // std::cout << "^^^^^^^^^^^^^" << '\n';
  // std::cout << c0max << '\n'<< c1max << '\n';
  // std::cout << "^^^^^^^^^^^^^" << '\n';
  //
  // std::cout << c0smax << '\n'<< c1smax << '\n';
  //
  // std::cout << v0<< "-------"<<v1 << '\n';

  // for (std::map<int,int>::iterator it=c0.begin(); it!=c0.end(); ++it) {
  //   std::cout << it->first <<"aasd" << it->second<< '\n';
  // }


    // for (const auto& [key, value] : c1){
    //       if(value > c1max){
    //         c1smax = c1max;
    //         c1max = value;
    //       }else{
    //         if (value > cs1max) {
    //           cs1max = value;
    //         }
    //       }
    //   }

  // std::cout << N<< '\n'<< c0max << '\n'<< c1max << '\n';
  int ans = N - c0max - c1max;
  if (v0 == v1) {
    if (c1max + c0smax > c1smax + c0smax) {
      ans = N - c1max - c0smax;
    }else{
      ans = N - c1smax - c0max;

    }
  }

  std::cout << ans<< '\n';


  return 0;
}