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>
#include <math.h>
#include <string.h>
#define min(a,b) a<b?a:b
int main()
{
    int sml,osv=1,esv=1,osc=1,esc=1,oc=1,s[100001]={0},poc=1,ec=1,pec=1,n,ev,ov,cnt=0,i,v[100001],t[100001]={0},odd[100001],even[100001];
    scanf("%d",&n);
   for(i=0;i<n;i++){
       scanf("%d",&v[i]);
       if(i%2==0){
           even[i/2]=v[i];
       }else{
           odd[(i-1)/2]=v[i];
       }
   }
   for(i=0;i<(n/2);i++){
       t[odd[i]]++;
   }
   for(i=0;i<100001;i++){
       if(t[i]>oc){
           osv=ov;
           osc=oc;
           oc=t[i];
           ov=i;
       }
   }
   for(i=0;i<((n+1)/2);i++){
       s[even[i]]++;
   }
   for(i=0;i<100001;i++){
       if(s[i]>ec&&i!=ov){
           esv=ev;
           esc=ec;
           ec=s[i];
           ev=i;
       }
   }
   if(ov!=ev){
    printf("%d",n-ec-oc);
    }else{
        sml=min(ec+osc,oc+esc);
        printf("%d",n-sml);}
    return 0;
}