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.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

	public static void main(String args[]) {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();

		int[] v = new int[n];

		Map<Integer,Integer> odd = new HashMap<>();
		Map<Integer,Integer> even = new HashMap<>();

		for(int i=0;i<n;i++) {
			v[i] = sc.nextInt();
			if(i%2 == 0) {
				if(even.containsKey(v[i])) {
					int temp = even.get(v[i]);
					temp++;
					even.put(v[i], temp);
				}else {
					even.put(v[i], 1);
				}
			}else {
				if(odd.containsKey(v[i])) {
					int temp = odd.get(v[i]);
					temp++;
					odd.put(v[i], temp);
				}else {
					odd.put(v[i], 1);
				}
			}
		}

		int max_even = Collections.max(even.values());
		int max_odd = Collections.max(odd.values());
		int ans = n - max_even - max_odd;
		if(even.keySet().size() == 1 && odd.keySet().size() == 1 && v[0] == v[1]) ans = n/2;
		System.out.println(ans);
	}

}