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 scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int[] v1 = new int[100001];
        int[] v2 = new int[100001];
        int max1 = 0;
        int m1=0;
        int m2=0;
        int max2 = 0;
        for (int i=0;i<n/2;i++){
            v1[scanner.nextInt()]++;
            v2[scanner.nextInt()]++;
        }
        for (int i=1;i<100001;i++){
            max1 = Math.max(max1,v1[i]);
            if (v1[i]==max1)m1=i;
            max2 = Math.max(max2,v2[i]);
            if (v2[i]==max2)m2=i;
        }
        if (max1>max2){
            for (int i=1;i<100001;i++){
                if (i!=m1)max2 = Math.max(max2,v2[i]);
            }
        }else if (max1<max2){
            for (int i=1;i<100001;i++){
                if (i!=m2)max1 = Math.max(max1,v1[i]);
            }
        }else {
            int j=0;
            int k=0;
            for (int i=1;i<100001;i++){
                if (i!=m1)j = Math.max(j,v2[i]);
                if (i!=m2)k = Math.max(k,v1[i]);
            }
            max2 = Math.max(j,k);
        }
        if (max1==max2&&m1==m2&&max1+max2==n){
            System.out.println(n/2);
        }else {
            System.out.println(n-max1-max2);
        }
    }
}