[Kotlin] Programmers 코딩테스트 입문 Day 11 수학, 반복문

주사위의 개수

class Solution {
    fun solution(box: IntArray, n: Int) = (box[0]/n) * (box[1]/n) * (box[2]/n)
}

 

 

 

합성수 찾기

class Solution {
    fun solution(n: Int) = n - countPrimes(n)

    fun countPrimes(size: Int): Int{
        var count = 0

        for (i in 1..size) {
            if (miniCount(i)) count++
        }

        return count
    }

    fun miniCount(n: Int): Boolean{
        for (j in 2 until n)
            if (n % j == 0) return false
        return true
    }
}

 

 

 

최댓값 만들기(1)

class Solution {
    fun solution(numbers: IntArray): Int {
        numbers.sort()
        return numbers[numbers.size-1]*numbers[numbers.size-2]
    }
}

 

 

 

팩토리얼

class Solution {
    fun factorials(n: Int): Int {
        return if (n <= 1) n else factorials(n - 1) * n
    }

    fun solution(n: Int): Int {
        var answer = 0

        for (i in 1..10) {
            if (factorials(i) <= n) {
                answer = i
            }
        }
        return answer
    }
}