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: Wrong Answer)

#include <stdio.h>

int main(void){
	int n,i,j,a[n],count=0;
  
  for(i=1;i<=n/2;i++){
  scanf("%d", &a[2*i-1]);
  scanf("%d", &a[2*i]);
  }
  
  for(i=0;i<n-1;i++){
	for(j=i+1;j<n-1;j++){
		if(a[2*j-1]==a[2*i-1]){
          	count++;
        }
    }
  }
  for(i=0;i<n-1;i++){
	for(j=i+1;j<n-1;j++){
		if(a[2*j]==a[2*i]){
          	count++;
        }
    }
  }
  for(i=0;i<n;i++){
	for(j=0;j<n && j!=i;j++){
		if(a[i]==a[j]){
          count++;
        }
    }
  }
          printf("%d", count);
}