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>
#include <stdlib.h>

#define LIMIT 100001

int main(void)
{
    int vi, vj;
    int n;
    int i;
    char c;
    int *ctr_vi, *ctr_vj;
    int MAX_vi, MAX_vj;
    int MAX_vi2, MAX_vj2;
    int index_MAX_vi, index_MAX_vj;
    
    
    MAX_vi = MAX_vj = 0;
    MAX_vi2 = MAX_vj2 = 0;
    
    
    scanf("%d", &n);
    
    
    ctr_vi = (int*)malloc(sizeof(int)*LIMIT);
    ctr_vj = (int*)malloc(sizeof(int)*LIMIT);
    
    
    for(i=0; i<LIMIT; i++)
        ctr_vi[i] = ctr_vj[i] = 0;
    
    
    for(i=1; i<=n/2; i++)
    {
        scanf("%d%c", &vi, &c);
        scanf("%d%c", &vj, &c);
        
        ctr_vi[vi]++;
        ctr_vj[vj]++;
    }
    
    
    for(i=1; i<LIMIT; i++)
    {
        if(ctr_vi[i] > MAX_vi)
        {
            MAX_vi2 = MAX_vi;
            MAX_vi = ctr_vi[i];
            index_MAX_vi = i;
        }
        else if(ctr_vi[i] > MAX_vi2)
        {
            MAX_vi2 = ctr_vi[i];
        }
        
        if(ctr_vj[i] > MAX_vj)
        {
            MAX_vj2 = MAX_vj;
            MAX_vj = ctr_vj[i];
            index_MAX_vj = i;
        }
        else if(ctr_vj[i] > MAX_vj2)
        {
            MAX_vj2 = ctr_vj[i];
        }
    }
    
    
    if(index_MAX_vi != index_MAX_vj)
        printf("%d\n", n-MAX_vi-MAX_vj);
    else
    {
        if(MAX_vi > MAX_vj)
            printf("%d\n", n-MAX_vi-MAX_vj2);
        else
            printf("%d\n", n-MAX_vj-MAX_vi2);
    }
    
    
    free(ctr_vi);
    free(ctr_vj);
    
    
    //system("pause");
    
    return 0;
}