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.Scanner;

public class Main {
  public static void main (String[] args) {
    final int MAX_V = 100000;
    Scanner in = new Scanner(System.in);

    while (in.hasNext()) {
      int n = in.nextInt();
      int halfN = n / 2;
      int[] v = new int[n];
      int[] countOdd = new int [MAX_V + 1];
      int[] countEven = new int [MAX_V + 1];

      for (int i = 0; i < v.length; ++i) {
        v[i] = in.nextInt();

        if (i % 2 == 0) {
          ++countEven[v[i]];
        } else {
          ++countOdd[v[i]];
        }
      }
      
      int evenMax1 = -1;
      int evenMax1Count = 0;
      for (int i = 0; i < countEven.length; ++i) {
        if (countEven[i] > evenMax1Count) {
          evenMax1 = i;
          evenMax1Count = countEven[i];
        }
      }

      countEven[evenMax1] = 0;
      int evenMax2Count = 0;
      for (int i = 0; i < countEven.length; ++i) {
        if (countEven[i] > evenMax2Count) {
          evenMax2Count = countEven[i];
        }
      }

      int oddMax1 = -1;
      int oddMax1Count = 0;
      for (int i = 0; i < countOdd.length; ++i) {
        if (countOdd[i] > oddMax1Count) {
          oddMax1 = i;
          oddMax1Count = countOdd[i];
        }
      }

      countOdd[oddMax1] = 0;
      int oddMax2Count = 0;
      for (int i = 0; i < countOdd.length; ++i) {
        if (countOdd[i] > oddMax2Count) {
          oddMax2Count = countOdd[i];
        }
      }

      if (evenMax1 != oddMax1) {
        System.out.println(halfN - evenMax1Count + halfN - oddMax1Count);
      } else {
        int min = Math.min(halfN - evenMax1Count + halfN - oddMax2Count, halfN - evenMax2Count + halfN - oddMax1Count);
        System.out.println(min);
      }
    }
  }
}