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: Wrong Answer)

private fun readInts() = readLine()!!.split(" ").map { it.toInt() }.toList()

fun main(args: Array<String>) {
    val n = readLine()!!.toInt()
    val v = readInts()

    val left = v.filterIndexed { index, value -> index % 2 == 0 }
    val right = v.filterIndexed { index, value -> index % 2 == 1 }

    val leftCountMap = mutableMapOf<Int, Int>(); left.forEach { value -> leftCountMap[value] = leftCountMap.getOrElse(value) { 0 } + 1 }
    val rightCountMap = mutableMapOf<Int, Int>(); right.forEach { value -> rightCountMap[value] = rightCountMap.getOrElse(value) { 0 } + 1 }

    var leftMax = 0 to 0
    var leftMaxHistory = mutableListOf<Pair<Int, Int>>()
    var leftMaxSec = 0 to 0
    for (pair in leftCountMap) {
        if (leftMax.second < pair.value) {
            leftMaxSec = leftMax
            leftMax = pair.toPair()
            leftMaxHistory = mutableListOf()
            continue
        }
        if (leftMax.second == pair.value) {
            leftMaxHistory.add(leftMax)
            leftMax = pair.toPair()
        }
        if (leftMaxSec.second < pair.value) {
            leftMaxSec = pair.toPair()
            leftMaxHistory = mutableListOf()
        }
    }

    var rightMax = 0 to 0
    var rightMaxHistory = mutableListOf<Pair<Int, Int>>()
    var rightMaxSec = 0 to 0
    for (pair in rightCountMap) {
        if (rightMax.second < pair.value) {
            rightMaxSec = rightMax
            rightMax = pair.toPair()
            rightMaxHistory = mutableListOf()
            continue
        }
        if (rightMax.second == pair.value) {
            rightMaxHistory.add(rightMax)
            rightMax = pair.toPair()
        }
        if (rightMaxSec.second < pair.value) {
            rightMaxSec = pair.toPair()
            rightMaxHistory = mutableListOf()
        }
    }

    val maxIsLeft = leftMax.second > rightMax.second
    val max = if (maxIsLeft) leftMax else rightMax
    val sec = if (leftMax.first != rightMax.first) {
        if (maxIsLeft) rightMax else leftMax
    } else {
        if (maxIsLeft){
            rightMaxHistory.maxBy { it.second } ?: rightMaxSec
        } else {
            leftMaxHistory.maxBy { it.second } ?: leftMaxSec
        }

    }

    println(n - (max.second + sec.second))
}