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.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();

		int[] odd = new int[n/2];
		int[] even = new int[n/2];

		for(int i = 0 ; i < n ; i++){
			if(i%2 != 0){
				odd[i/2] = sc.nextInt();
			}
			else{
				even[i/2] = sc.nextInt();
			}
		}

		sc.close();

		int[] checkodd = new int[100001];
		int[] checkeven = new int[100001];

		for(int i = 0 ; i < n/2 ; i++){
			checkodd[odd[i]] += 1;
			checkeven[even[i]] += 1;
		}

		int oddmax=0,evenmax=0,oddp=0,evenp=0;

		for(int i = 1 ; i <= 100000 ; i++){
			int oddtmp,eventmp;
			oddtmp = checkodd[i];
			eventmp = checkeven[i];

			if(oddmax < oddtmp){
				oddmax = oddtmp;
				oddp = i;
			}
			if(evenmax < eventmp){
				evenmax = eventmp;
				evenp = i;
			}
		}
/*
		System.out.println(oddmax);
		System.out.println(oddp);

		System.out.println(evenmax);
		System.out.println(evenp);
*/
		int ans = 0;

		if(oddmax == n/2 && evenmax == n/2){
			if(oddp == evenp){
				System.out.println(n/2);
			}
			else{
				System.out.println(0);
			}
		}

		else if(oddmax == n/2){
			System.out.println((n/2)-evenmax);
		}
		else if(evenmax == n/2){
			System.out.println((n/2)-oddmax);
		}
		else{
			System.out.println(n-oddmax-evenmax);
		}

	}
}