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: Runtime Error)

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main{
	public static void main(String[] args)throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		String[] strs = br.readLine().split(" ");
		
		int[] v1 = new int[100000];
		int[] v2 = new int[100000];
		
		for(int i = 0 ; i < v1.length ; i++){
			v1[i] = 0;
			v2[i] = 0;
		}
		
		for(int i = 0 ; i < n ; i++){
			if(i%2 == 0){
				v1[Integer.parseInt(strs[i])]++;
			}else{
				v2[Integer.parseInt(strs[i])]++;
			}
		}
		int max11 = 0;
		int max12 = 0;
		int max11id = 0;
		int max12id = 0;
		int max21 = 0;
		int max22 = 0;
		int max21id = 0;
		int max22id = 0;
		
		for(int i = 0 ; i < v1.length ; i++){
			if(v1[i] > max11){
				max12 = max11;
				max12id = max11id;
				max11 = v1[i];
				max11id = i;
			}else if(v1[i] > max12){
				max12 = v1[i];
				max12id = i;
			}
		}
		for(int i = 0 ; i < v2.length ; i++){
			if(v2[i] > max21){
				max22 = max21;
				max22id = max21id;
				max21 = v2[i];
				max21id = i;
			}else if(v2[i] > max22){
				max22 = v1[i];
				max22id = i;
			}
		}
		
		if(max11id != max21id){
			System.out.println((n - max11 - max21));
		}else{
			if((n - max11 - max22) < (n - max12 - max21)){
				System.out.println((n - max11 - max22));
			}else{
				System.out.println((n - max12 - max21));
			}
		}
	}
}