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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.HashMap;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        java.util.Map<Integer, Integer> oddMap = new HashMap<>();
        java.util.Map<Integer, Integer> evenMap = new HashMap<>();
        int currentKey = 0;
        for (int i = 0; i < n; i++) {
            currentKey = sc.nextInt();
            if (i % 2 == 0) {
                oddMap.put(currentKey, oddMap.getOrDefault(currentKey, 0) + 1);
            } else {
                evenMap.put(currentKey, evenMap.getOrDefault(currentKey, 0) + 1);
            }
        }

        Integer o1_k = -1;
        Integer e1_k = -1;
        Integer o2 = -1;
        Integer e2 = -1;

        Integer o1 = -1;
        Integer e1 = -1;

        for (java.util.Map.Entry<Integer, Integer> entry : oddMap.entrySet()) {
            if (entry.getValue() > o1) {
                o2 = o1;
                o1_k = entry.getKey();
                o1 = entry.getValue();
            } else if (entry.getValue() > o2){
                o2 = entry.getValue();
            }
        }

        for (java.util.Map.Entry<Integer, Integer> entry : evenMap.entrySet()) {
            if (entry.getValue() > e1) {
                e2 = e1;
                e1_k = entry.getKey();
                e1 = entry.getValue();
            } else if (entry.getValue() > e2){
                e2 = entry.getValue();
            }
        }

        if (o1_k.equals(e1_k)) {
            System.out.println(Math.min(n - o2 - e1, n - o1 - e2));
        } else {
            System.out.println(n - o1 - e1);
        }


    }
}