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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int a[100100],b[100100],n,tem;

int main()
{
    scanf("%d",&n);
    int nn=n,maxn=0;
    while(n)
    {
        scanf("%d",&tem);n--;
        a[tem]++;
        if(tem>maxn)maxn=tem;
        scanf("%d",&tem);n--;
        b[tem]++;
       if(tem>maxn)maxn=tem;
    }
    int m1=0,mm1=0,mm2=0,m2=0,p1,p2;
    for(int i=0;i<=maxn;i++)
    {
        if(a[i]>m1)m1=a[i],p1=i;
        if(b[i]>m2)m2=b[i],p2=i;
    }
    for(int i=0;i<=maxn;i++)
    {
        if(a[i]!=m1&&a[i]>mm1)mm1=a[i];
        if(b[i]!=m2&&b[i]>mm2)mm2=b[i];
    }
    if(p1==p2)
        cout<<nn-max(m1+mm2,mm1+m2);
    else cout<<nn-(m1+m2);
    return 0;
}