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.io.*;
import java.util.*;

public class Main {
    public static void main(String args[]) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        br.readLine();
        String[] ips = br.readLine().split(" ");
        int len = ips.length;
        int[] cnta = new int[100005];
        int[] cntb = new int[100005];
        int mxa = 0;
        int mxb = 0;
        int mxa2 = 0;
        int mxb2 = 0;
        int besta = -1;
        int bestb = -1;
        
        for(int i = 0; i < len; i+=2){
            int curr = Integer.parseInt(ips[i]);
            cnta[curr]++;
            if(cnta[curr] > mxa){
                mxa = cnta[curr];
                besta = curr;
            }
        }
        
        for(int i = 1; i < len; i+=2){
            int curr = Integer.parseInt(ips[i]);
            cntb[curr]++;
            if(cntb[curr] > mxb){
                mxb = cntb[curr];
                bestb = curr;
            }
        }
        
        for(int i = 0; i < 100005; ++i){
            int f = cnta[i];
            int f2 = cntb[i];
            if(f <= mxa && i!=besta)
                mxa2 = Math.max(mxa2, f);
            if(f2 <= mxb && i!=bestb)
                mxb2 = Math.max(mxb2, f2);
        }
        
        int res = 0;
        if(besta != bestb){
            System.out.println(len-mxa-mxb);
            return;
        }
        res = Math.min(len-mxa2-mxb, len-mxa-mxb2);
        System.out.println(res);
    }
}