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.HashSet;
import java.util.Set;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;

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[] str_vs = br.readLine().split(" ");
        int vs[] = new int[n];
        int[] count1 = new int[100001];
        int[] count2 = new int[100001];
        int ans = 0;
        
        for (int i = 0; i < n; i++) {
            vs[i] = Integer.parseInt(str_vs[i]);
        }
        
        for (int i = 0; i < n; i+=2) {
            count1[vs[i]]++;
        }
        
        int max1 = 0;
        int second1 = 0;
        //int second_i1 = 0;
        int max_i1 = 0;
        for (int i = 0; i < 100001; i++) {
            if (max1<count1[i]) {
                //second1 = max1;
                //second_i1 = max_i1;
                max1 = count1[i];
                max_i1 = i;
            }
        }
        
        //ans += n/2-max1;
        //count = new int[100001];
        
        for (int i = 1; i < n; i+=2) {
            count2[vs[i]]++;
        }
        
        int max2 = 0;
        int second2 = 0;
        //int second_i2;
        int max_i2 = 0;
        for (int i = 0; i < 100001; i++) {
            if (max2<count2[i]) {
                //second2 = max2;
                //second_i2 = max_i2;
                max2 = count2[i];
                max_i2 = i;
            }
        }
        
        Arrays.sort(count1);
        Arrays.sort(count2);
        
        //System.out.println(max1);
        //System.out.println(max2);
        
        if (max_i1==max_i2) {
            //System.out.println("aaa");
            if (max1>max2) {
                //System.out.println("bbb");
                ans = n/2-count1[100000] + n/2-count2[99999];
            }
            else if (max1<max2) {
                //System.out.println("ccc");
                ans = n/2-count1[99999] + n/2-count2[100000];
            }
            else {
                //System.out.println("ddd");
                if (count1[99999]>count2[99999]) {
                    //System.out.println("eee");
                    ans = n/2-count1[99999] + n/2-count2[100000];
                }
                else {
                    //System.out.println("fff");
                    ans = n/2-count1[100000] + n/2-count2[99999];
                }
            }
            
        }
        else {
            ans = n/2-count1[100000] + n/2-count2[100000];
        }
        
        //ans += n/2-max2;
        System.out.println(ans);
    }
}