recursion-iteration.kt

class Solution {
    fun reverseStrRecursively(str: String): String {
        return if (str.length == 1) str
        else reverseStrRecursively(str.substring(1, str.length)) + str.substring(0, 1)
    }

    fun reverseStrIteratively(str: String): String {
        val result = mutableListOf<String>()

        var i = str.length
        do {
            result.add(str.substring(i-1, i))
            i--
        } while (result.size  != str.length)

        return result.joinToString("")
    }
}

fun main() {
    println(Solution().reverseStrRecursively("abcd"))
    println(Solution().reverseStrIteratively("abcd"))
}