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.*;
import java.lang.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a[] = new int[n / 2];
        int b[] = new int[n / 2];
        for (int i = 0; i < n / 2; i++) {
            a[i] = sc.nextInt();
            b[i] = sc.nextInt();
        }
        Arrays.sort(a);
        Arrays.sort(b);
        int counta = 1;
        int countb = 1;
        ArrayList<Integer> lista = new ArrayList<Integer>();
        ArrayList<Integer> listacount = new ArrayList<Integer>();
        ArrayList<Integer> listb = new ArrayList<Integer>();
        ArrayList<Integer> listbcount = new ArrayList<Integer>();

        for(int i = 0; i < n / 2 - 1; i++){
            if (a[i] != a[i + 1]) {
                lista.add(a[i]);
                listacount.add(counta);
                counta = 1;
            }else{
                counta++;
            }
            if (b[i] != b[i + 1]) {
                listb.add(b[i]);
                listbcount.add(countb);
                countb = 1;
            } else {
                countb++;
            }
        }
        
        lista.add(a[n / 2 - 1]);
        listacount.add(counta);
        lista.add(-1);
        listacount.add(0);
        
        listb.add(b[n / 2 - 1]);
        listbcount.add(countb);
        listb.add(-1);
        listbcount.add(0);
        
        int maxa = 0;
        for(int i = 0; i < listacount.size(); i++){
            maxa = Math.max(listacount.get(i), maxa);
        }
        int maxb = 0;
        for(int i = 0; i < listbcount.size(); i++){
            maxb = Math.max(listbcount.get(i), maxb);
        }
        if (lista.get(listacount.indexOf(maxa)) != listb.get(listbcount.indexOf(maxb)) || lista.get(listacount.lastIndexOf(maxa)) != listb.get(listbcount.indexOf(maxb)) || lista.get(listacount.indexOf(maxa)) != listb.get(listbcount.lastIndexOf(maxb))) {
            System.out.println(n - maxa - maxb);
        }else{
            listacount.remove((Integer)(maxa));
            listbcount.remove((Integer)(maxb));
            int maxas = 0;
            for (int i = 0; i < listacount.size(); i++) {
                maxas = Math.max(listacount.get(i), maxas);
            }
            int maxbs = 0;
            for (int i = 0; i < listbcount.size(); i++) {
                maxbs = Math.max(listbcount.get(i), maxbs);
            }
            System.out.println(Math.min(n - maxas - maxb, n - maxa - maxbs));
        }
    }
}