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

public class Main {
	static int n;

	public static void main(String[] args) {
		int i;
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		int v[] = new int[n];
		for (int j = 0; j < n; j++) {
			v[j] = sc.nextInt();
		}
		ArrayList<Integer> kisuu = new ArrayList<>();
		ArrayList<Integer> gusuu = new ArrayList<>();

		for (i = 0; i < n; i++) {
			if (i % 2 == 0) {
				gusuu.add(v[i]);
			} else {
				kisuu.add(v[i]);
			}
		}
//		System.out.println("kisuu" + Main.maxcount(kisuu));
//		System.out.println("gusuu" + Main.maxcountY(gusuu, Main.maxNum(kisuu)));
//		System.out.println("gusuu Num" + Main.maxNum(gusuu));
		//System.out.println((kisuu.size() - Main.maxcount(kisuu)) + (gusuu.size() - Main.maxcountY(gusuu, Main.maxNum(kisuu))));
		System.out.println(kisuu.size() - Main.maxcount(kisuu));
	}
	static int maxcount(ArrayList<Integer> list) {
		// メモ化
		HashMap<Integer, Integer> memo = new HashMap<>();
		int max = 0;
		for (int i = 0; i < list.size(); i++) {
			int count = 0;
			if (!memo.containsKey(list.get(i))) {
				for (int j = 0; j < list.size(); j++) {
					if (list.get(i) == list.get(j)) {
						count++;
					}
				}
				memo.put(list.get(i), count);
				//count--;
				max= Math.max(max, count);
			}
		}
		return max;
	}
	// 一番多い数を返す
	static int maxNum(ArrayList<Integer> list) {
		int max = 0;
		int a = 0;
		for (int i = 0; i < list.size(); i++) {
			int count = 0;
			for (int j = 0; j < list.size(); j++) {
				if (list.get(i) == list.get(j)) {
					count++;
				}
			}
			//count--;
			max= Math.max(max, count);
			if (max < count) {
				a = i;
			}
		}
		return list.get(a);
	}
	static int maxcountY(ArrayList<Integer> list, int x) {
		int max = 0;
		for (int i = 0; i < list.size(); i++) {
			int count = 0;
			for (int j = 0; j < list.size(); j++) {
				if (list.get(i) == list.get(j) && !(list.get(i) == x)) {
					count++;
				}
			}
			//count--;
			max= Math.max(max, count);
		}
		return max;
	}
}