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()
{
    int n,i,par[100001],impar[100001],a;

    for (i=1; i<=100001; i++)
    {
        par[i]=0;
        impar[i]=0;
    }

    scanf ("%d",&n);

    for (i=1; i<=n; i++)
    {
        scanf ("%d",&a);
        if (i%2==1)
        {
            impar[a]++;
        }
        else
        {
            par[a]++;
        }
    }

    int maxpar=0,maxpar2=0,maximpar=0,maximpar2=0;
    int valpar,valimpar;

    for (i=1; i<=100001; i++)
    {
        if (impar[i]>maximpar)
        {
            maximpar=impar[i];
            valimpar=i;
        }
        else if (impar[i]>maximpar2)
        {
            maximpar2=impar[i];
        }

        if (par[i]>maxpar)
        {
            maxpar=par[i];
            valpar=i;
        }
        else if (par[i]>maxpar2)
        {
            maxpar2=par[i];
        }
    }

    if (valpar==valimpar)
    {
        if (maxpar2>maximpar2)
        {
            printf ("%d",n-maxpar2-maximpar);
        }
        else
        {
            printf ("%d",n-maxpar-maximpar2);
        }
    }
    else
    {
        printf ("%d",n-maxpar-maximpar);
    }

    return 0;
}