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.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] v = new int[n];
        for(int i=0; i<n; i++){
            v[i]  = sc.nextInt();
        }
        sc.close();

        int[] num1 = new int[100010];
        int[] num2 = new int[100010];

        for(int i=0; i<n; i++){
            if(i%2 == 0){
                num1[v[i]]++;
            }else{
                num2[v[i]]++;
            }
        }

        int max11 = 0;
        int max12 = 0;
        int max21 = 0;
        int max22 = 0;
        int pos1 = 0;
        int pos2 = 0;

        for(int i=0; i<100010; i++){
            if(num1[i] > max11){
                max12 = max11;
                max11 = num1[i];
                pos1 = i;
            }else if(num1[i] > max12){
                max12 = num1[i];
            }
            if(num2[i] > max21){
                max22 = max21;
                max21 = num2[i];
                pos2 = i;
            }else if(num2[i] > max22){
                max22 = num2[i];
            }
        }

        if(pos1 != pos2){
            System.out.println(n - max11 - max21);
        }else{
            int ans = Math.max(max11 + max22, max12 + max21);
            System.out.println(n - ans);
        }

    }
}