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: Accepted)

import java.util.Comparator;
import java.util.stream.IntStream;

public class Main {
    private static java.util.Scanner scanner = new java.util.Scanner(System.in);

    public static void main(String[] args) {
        int n = scanner.nextInt();
        int[] u1 = new int[n / 2], u2 = new int[n / 2], count1 = new int[100001], count2 = new int[100001];
        for (int i = 0; i < n / 2; i++) {
            count1[u1[i] = scanner.nextInt()]++;
            count2[u2[i] = scanner.nextInt()]++;
        }

        int max1 = IntStream.range(0, 100001)
                .boxed()
                .max(Comparator.comparingInt(i -> count1[i]))
                .orElse(0);
        int max2 = IntStream.range(0, 100001)
                .boxed()
                .max(Comparator.comparingInt(i -> count2[i]))
                .orElse(0);
        if (max1 == max2) {
            int next1 = IntStream.range(0, 100001)
                    .filter(i -> i != max1)
                    .boxed()
                    .max(Comparator.comparingInt(i -> count1[i]))
                    .orElse(0);
            int next2 = IntStream.range(0, 100001)
                    .filter(i -> i != max2)
                    .boxed()
                    .max(Comparator.comparingInt(i -> count2[i]))
                    .orElse(0);
            System.out.println(n - Math.max(count1[next1] + count2[max2], count1[max1] + count2[next2]));
        } else {
            System.out.println(n - count1[max1] - count2[max2]);
        }
    }
}