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++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,maxx=0,cnt=0,chek1=0,chek2=0;
 int a[100001],x[100001]={};
 cin>>n;
	for(int i=0;i<n;i++) cin>>a[i];
 for(int i=0;i<n;i+=2){
        x[a[i]]++;
        if(x[a[i]]>maxx) maxx=x[a[i]],chek1=a[i];
    }
  int x1[100001]={};
  maxx=0;
	 for(int i=1;i<n;i+=2){
        x1[a[i]]++;
        if(x1[a[i]]>maxx && a[i]!=chek1) maxx=x1[a[i]],chek2=a[i];
    }
   for(int i=0;i<n;i+=2){
        if(a[i]!=chek1) cnt++;
    }
    for(int i=1;i<n;i+=2){
        if(a[i]!=chek2) cnt++;
    }
    cout<<cnt;
}