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.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int[] v = new int[n];
    int[] e = new int[100001];
    int[] o = new int[100001];
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextInt();
      if (i % 2 == 0) {
        e[v[i]]++;
      } else {
        o[v[i]]++;
      }
    }
    int e1 = 0;
    int e2 = 0;
    int o1 = 0;
    int o2 = 0;
    for (int i = 1; i <= 100000; i++) {
      if (e[i] > e[e1]) {
        e1 = i;
      }
      if (o[i] > o[o1]) {
        o1 = i;
      }
    }
    for (int i = 1; i <= 100000; i++) {
      if (e[e1] >= e[i] && e[i] > e[e2] && e1 != i) {
        e2 = i;
      }
      if (o[o1] >= o[i] && o[i] > o[o2] && o1 != i) {
        o2 = i;
      }
    }
    if (e1 != o1) {
      int ans = 0;
      for (int i = 0; i < n; i++) {
        if (i % 2 == 0 && v[i] != e1) {
          ans++;
        }
        if (i % 2 == 1 && v[i] != o1) {
          ans++;
        }
      }
      System.out.println(ans);
    } else {
      int ans1 = 0;
      for (int i = 0; i < n; i++) {
        if (i % 2 == 0 && v[i] != e1) {
          ans1++;
        }
        if (i % 2 == 1 && v[i] != o2) {
          ans1++;
        }
      }
      int ans2 = 0;
      for (int i = 0; i < n; i++) {
        if (i % 2 == 0 && v[i] != e2) {
          ans2++;
        }
        if (i % 2 == 1 && v[i] != o1) {
          ans2++;
        }
      }
      System.out.println(Math.min(ans1, ans2));
    }
  }
}