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.*;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int[] v = new int[n];
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextInt();
    }
    int[] o = new int[100001];
    int[] e = new int[100001];
    for (int i = 0; i < n; i++) {
      if (i % 2 == 0) e[v[i]]++;
      else o[v[i]]++;
    }
    int o1 = 0, o2 = 0, e1 = 0, e2 = 0, o1i = 0, o2i = 0, e1i = 0, e2i = 0;
    for (int i = 1; i <= 100000; i++) {
      if (o2 < o[i]) {
        o2 = o[i];
        o2i = i;
      }
      if (o1 < o2) {
        int temp = o1;
        o1 = o2;
        o2 = temp;
        temp = o1i;
        o1i = o2i;
        o2i = temp;
      }
      if (e2 < e[i]) {
        e2 = e[i];
        e2i = i;
      }
      if (e1 < e2) {
        int temp = e1;
        e1 = e2;
        e2 = temp;
        temp = e1i;
        e1i = e2i;
        e2i = temp;
      }
    }
    System.out.println(o1 + " " + o1i + " " + e1 + " " + e1i);
    if (o1i != e1i) System.out.println(n - o1 - e1);
    else System.out.println(Math.min(n - o1 - e2, n - o2 - e1));
  }
}