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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {

    C.init()
    C.execute()

}

class C {

    companion object {
        var N = 0
        private var numberMap1 = mutableMapOf<Int, Int>()
        private var numberMap2 = mutableMapOf<Int, Int>()

        fun init() {

            N = readLine()!!.toInt()

            readLine()!!.split(" ").forEachIndexed { index, s ->

                val num = s.toInt()
                if (index % 2 == 0) {
                    if (numberMap1.containsKey(num)) {
                        numberMap1[num] = numberMap1[num]!! + 1
                    } else {
                        numberMap1[num] = 1
                    }
                } else {
                    if (numberMap2.containsKey(num)) {
                        numberMap2[num] = numberMap2[num]!! + 1
                    } else {
                        numberMap2[num] = 1
                    }
                }
            }
        }

        fun execute() {

            var num1Entry = numberMap1.maxBy {
                it.value
            }!!
            var num2Entry = numberMap2.maxBy {
                it.value
            }!!

            numberMap1.remove(num1Entry.key)
            numberMap2.remove(num2Entry.key)


            val num1MostSeeEntry = num1Entry
            val num2MostSeeEntry = num2Entry

            // 異なる数字かチェック
            if (num1Entry.key != num2Entry.key) {
                print(N - num1Entry.value - num2Entry.value)
                return
            }

            // 同じ数字の場合
            // 回数が異なる場合
            if (num1Entry.value > num2Entry.value) {
                // num1の方が多いってことは、num2には２個以上あるはず
                print(N - num1Entry.value - numberMap2.maxBy {
                    it.value
                }!!.value)
                return
            } else if (num1Entry.value < num2Entry.value) {
                // num2の方が多いってことは、num1には２個以上あるはず
                print(N - numberMap1.maxBy {
                    it.value
                }!!.value - num2Entry.value)
                return
            }

            // 同じ数字の場合
            // 回数も同じ場合
            if (numberMap1.size == 0) {
                print(num1Entry.value)
                return
            }

            // 同じ数字かつ出現回数が等しい場合
            // 次の値を見る
            num1Entry = numberMap1.maxBy { it.value }!!
            num2Entry = numberMap2.maxBy { it.value }!!

            if (num1Entry.value > num2Entry.value) {
                print(N - num1Entry.value - num2MostSeeEntry.value)
            } else {
                print(N - num2Entry.value - num1MostSeeEntry.value)
            }
            return
        }
    }
}