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<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
	int tot[2][100010];
	int n,ans,mi=100010,ma=0;
int main()
{
	int x;
	scanf("%d",&n);
	ans=n;
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&x);
		tot[i&1][x]++;
		mi=min(mi,x);
		ma=max(ma,x);
	}
	int ma0=0,ma1=0,t0=0,t1=0;
	for(int i=mi;i<=ma;i++)
	{
		if(ma0<tot[0][i]) ma0=tot[0][i],t0=i;
		if(ma1<tot[1][i]) ma1=tot[1][i],t1=i;
	}
	if(t0==t1)
	{
		int ma2=0;
		for(int i=mi;i<=ma;i++)
			if(t0!=i) ans=max(ans,max(tot[0][i],tot[1][i]));
		ma0=ma2;
	}
	printf("%d",n-ma0-ma1);
}