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 Scala (2.11.7) (judge verdict: Wrong Answer)

object Main{
  def main(args: Array[String]){
    val sc=new java.util.Scanner(System.in)
    val n=sc.nextInt()
    val std=mysprit(n,sc).map(x=>(List(0,0)::mysort(x,Nil))).sortBy(l=>l(0)(1)-l(1)(1))
    std match{
      case List(a:List[List[Int]],b:List[List[Int]]) if a(0)(0)==b(0)(0) => println(n-(a(1)(1)+b(0)(1)))
      case List(a:List[List[Int]],b:List[List[Int]]) => println(n-(a(0)(1)+b(0)(1)))
    }
  }
  def mysort(l:List[Int],r:List[List[Int]]) : List[List[Int]] = {
    l.sorted match{
      case Nil => r
      case x::xs => {
        val n = xs.indexWhere(_!=x)
        mysort(xs.drop(n), (x :: n+1 :: Nil) :: r )
      }
    }
  }
  def mysprit(n:Int,s:java.util.Scanner):List[List[Int]] = {
    def myspritlocal(c:Int,l1:List[Int],l2:List[Int]):List[List[Int]] ={
      c match{
        case 0 => List(l1,l2)
        case a:Int => myspritlocal(a-2,s.nextInt()::l1,s.nextInt()::l2)
      }
    }
    myspritlocal(n,Nil,Nil)
  }
}