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: Time Limit Exceeded)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.valueOf(sc.next());
		int v[] = new int[N];
		int v1[] = new int[N / 2];
		int v2[] = new int[N / 2];
		int cnt1 = 0;
		int cnt2 = 0;
		int cntMin1 = 1000;
		int cntMin2 = 1000;
		boolean onajiFlg = true;
		int befNum = 0;
		for (int i = 0; i < N; i++) {
			v[i] = Integer.valueOf(sc.next());
			if(i==0) {
				befNum = v[0];
			}else if(befNum != v[i]) {
				onajiFlg=false;
			}
			if (i % 2 == 0) {
				v1[cnt1] = Integer.valueOf(v[i]);
				cnt1++;
			}else {
				v2[cnt2] = Integer.valueOf(v[i]);
				cnt2++;
			}
		}

		cnt1 = 0;
		cnt2 = 0;
		for (int i = 0; i < N/2; i++) {
			for (int j = 0; j < N/2; j++) {
				if(i==j) continue;
				if(v1[i]!=v1[j]) {
					cnt1++;
				}
				if(v2[i]!=v2[j]) {
					cnt2++;
				}
				cntMin1= Math.min(cnt1, cntMin1);
				cntMin2= Math.min(cnt2, cntMin2);
			}
		}

		sc.close();
		if(onajiFlg) {
			System.out.println(N/2);
		}else {
			System.out.println(cntMin1+cntMin2);
		}
	}

}