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.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] odd = new int[100001]; // iが奇数であるviからなる数列Oについて、1-100000までのそれぞれの数が存在する個数
		int[] even = new int[100001];
		Arrays.fill(odd, 0);
		Arrays.fill(even, 0);
		for (int i = 1; i <= n; i++) {
			int v = sc.nextInt();
			if (i%2 != 0) {
				odd[v]++;
			} else {
				even[v]++;
			}
		}

		int odd_max1 = 0;
		int odd_max2 = 0;
		for (int i = 1; i < 100000; i++) {
			if (odd[i] > odd[odd_max1]) {
				odd_max2 = odd_max1;
				odd_max1 = i;
			} else if (odd[i] > odd[odd_max2]) {
				odd_max2 = i;
			}
		}
		int even_max1 = 0;
		int even_max2 = 0;
		for (int i = 2; i < 100001; i++) {
			if (even[i] > even[even_max1]) {
				even_max2 = even_max1;
				even_max1 = i;
			} else if (even[i] > even[even_max2]) {
				even_max2 = i;
			}
		}
		int not_rewrited = 0;
		if (odd_max1 == even_max1) {
			not_rewrited = Math.max(odd[odd_max1] + even[even_max2], odd[odd_max2] + even[even_max1]);
		} else {
			not_rewrited = odd[odd_max1] + even[even_max1];
		}
		System.out.println(n - not_rewrited);
	}
}