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# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using static System.Console;

class plmko{
  static void Main(){
    int n = int.Parse(ReadLine());
    string[] num =ReadLine().Split(' ');
    int[] even = new int[200000];
    int[] odd = new int[200000];
    int maxe=0,maxo=0,maxe2=0,maxo2=0;
    for(int i=0;i<n;i++){
      if(i%2==0){
        int a = int.Parse(num[i]);
        even[a]++;
      }else{
        int b = int.Parse(num[i]);
        odd[b]++;
      }
    }
    int che =-1,che2=-1;
    for(int i=0;i<=100000;i++){
      if(even[i] > maxe){
        che2=che;
        che = i;
        maxe2 =maxe;
maxe = even[i];
}}

int cho =-1,cho2=-1;
    for(int i =0;i<=100000;i++){
      if(odd[i] > maxo){
        cho2=cho;
        cho =i;
        maxo2 =maxo;
        maxo = odd[i];
      }
    }

    if(che ==cho){
      if(maxe > maxo){
        WriteLine(n-maxe-maxo2);
      }else if(maxo > maxe){
        WriteLine(n-maxe2-maxo);
      }else{
        if(maxo2> maxe2){
           WriteLine(n-maxo2-maxe);
        }else{
            WriteLine(n-maxo-maxe2);
        }
      }
    }else{
      WriteLine(n-maxe-maxo);
    }
  }
}