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 <algorithm>
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int> even(100001, 0), odd(100001, 0);
    for (int i = 1; i <= n; i++)
    {
        int v;
        cin >> v;
        if (i % 2 == 1)
        {
            odd[v]++;
        }
        else
        {
            even[v]++;
        }
    }
    auto even_pos = max_element(even.begin(), even.end());
    auto odd_pos = max_element(odd.begin(), odd.end());
    if (distance(even.begin(), even_pos) == distance(odd.begin(), odd_pos))
    {
        if (*even_pos < *odd_pos)
        {
            *even_pos = 0;
        }
        else
        {
            *odd_pos = 0;
        }
    }
    const int rewrite_num = n - *max_element(even.begin(), even.end()) - *max_element(odd.begin(), odd.end());
    cout << rewrite_num << endl;
}