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 5.4.1) (judge verdict: Time Limit Exceeded)

#include<stdio.h>

int main(){
  int N,od=0,ev=0,count1,count2,tmp1=0,tmp2=0;
  scanf("%d",&N);
  int a[N],odd[N/2],eve[N/2];
  for(int i=0;i<N;i++) scanf("%d",&a[i]);

  for(int i=0;i<N;i++){
    if(i%2==0){
      eve[ev]=a[i];ev++;
    }
    if(i%2==1){
      odd[od]=a[i];od++;
    }
  }
  //for(int i=0;i<N/2;i++){
    //printf("%d %d\n",eve[i],odd[i]);
  //}
  for(int i=0;i<N/2;i++){
    count1=0,count2=0;
    for(int j=0;j<N/2;j++){
      if(eve[i]==eve[j])count1++;
      if(odd[i]==odd[j])count2++;
    }
    if(count1>tmp1) tmp1=count1;//printf("tmp1%d\n",tmp1);
    if(count2>tmp2) tmp2=count2;//printf("tmp2%d\n",tmp2);
    if(count1>=N/2 && count2>=N/2)break;
  }

  if(tmp1 == tmp2 && eve[0]==odd[0]){
    printf("%d",N/2);
  }
  else printf("%d",N-tmp1-tmp2);
}