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.*;
import java.lang.*;
public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();
		int[] vOdd = new int[100001];
		int[] vEven = new int[100001];
		int maxOdd=0,maxEven=0,maxNumOdd=0,maxNumEven=0;
		for( int i=1; i<=N/2; i++ ){
			vOdd[sc.nextInt()]++;
			vEven[sc.nextInt()]++;
		}
		for( int i=1; i<=100000; i++ ){
			if( vOdd[i]>maxOdd ){
				maxOdd = vOdd[i];
				maxNumOdd = i;
			}
			if( vEven[i]>maxEven ){
				maxEven = vEven[i];
				maxNumEven = i;
			}
		}
		Arrays.sort(vOdd);
		Arrays.sort(vEven);
		int ans = 0;
		if( maxNumOdd!=maxNumEven ){
			ans = N - maxOdd - maxEven;
		}else{
			if( maxOdd==maxEven ){
				ans = N - maxOdd - Math.max(vOdd[99999],vEven[99999]);
			}else{
				if( maxOdd > maxEven ){
					if( maxOdd==vOdd[99999] ){
						ans = N - maxOdd - maxEven;
					}
					if( maxOdd > vOdd[99999] ){
						ans = N - maxOdd - vOdd[99999];
					}
				}
				if( maxEven > maxOdd ){
					if( maxEven==vEven[99999] ){
						ans = N - maxOdd - maxEven;
					}
					if( maxEven > vEven[99999] ){
						ans = N - maxEven - vEven[99999];
					}
				}
			}
		} 
		System.out.println(ans);     
	}
}