Mystical Coding: Parallel String and List Processing in Kotlin

Introduction

Welcome to a new session, where we are embarking on a journey into the mystical territory of combined string and list operations. Have you ever thought about how to update a string and a list in parallel while a specific condition holds true? That's precisely what we'll explore today, all in the context of a real-world scenario related to a mystery novel book club. Get ready to dive in!

Task Statement

Our mission today is to generate a unique encoded message for a book club. Here's the fun part: to create a cryptic message, we will process a string and a list of numbers simultaneously and stop once a given condition is satisfied. For the string, our task is to replace each letter with the next alphabetical letter and then reverse the entire updated string. For the list of numbers, our task is to divide each number by 2, round the result, and accumulate the rounded numbers until their total exceeds 20 . When the accumulated total exceeds 20, we immediately stop the process and return the updated string and the as-yet-unprocessed numbers in their original order. Example Consider the input string "books" and the list listOf(10, 20, 30, 50, 100) . We start our process with an empty string and a sum of 0 . For the first character'b' in "books", we replace it with the next alphabet'c' . For the corresponding number 10 in the list, we divide it by 2 and round it. The result is 5 . The sum after the first operation is 5, which is less than 20, so we continue to the next character. For the next character'o', we replace it with'p' . For the corresponding number 20 in the list, half and rounded is 10 . The sum after the second operation is 15 (5 + 10). The sum still doesn't exceed 20, so we move to the third character. For the next character'o', we replace it with'p' . For the corresponding number 30 in the list, half and rounded is 15 . When we add this 15 to the previously calculated sum of 15, it totals 30, which is more than 20 . So, we stop the process here. We have processed'b','o', and'o' from the word "books" and replaced them with'c','p', and'p' respectively to get "cpp" . After reversing, we get "ppc" . For the list, we exclude any numbers that we have processed. Hence, we exclude the first three numbers, and the list becomes [50, 100] . So the output should be "ppc 50, 100" .

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Kotlin

fun solution(inputString: String, numbers: List<Int>): String {
    var result = ""
    var sumSoFar = 0

fun solution(inputString: String, numbers: List<Int>): String {
    var result = ""
    var sumSoFar = 0

Kotlin

import kotlin.math.roundToInt

fun solution(inputString: String, numbers: List<Int>): String {
    val result = StringBuilder()
    var sumSoFar = 0
    var i = 0
    while (i < inputString.length && sumSoFar <= 20) {
        result.append(if (inputString[i] == 'z') 'a' else inputString[i] + 1)
        val halfNumber = (numbers[i] / 2.0).roundToInt()
        sumSoFar += halfNumber
        i++
    }

import kotlin.math.roundToInt

fun solution(inputString: String, numbers: List<Int>): String {
    val result = StringBuilder()
    var sumSoFar = 0
    var i = 0
    while (i < inputString.length && sumSoFar <= 20) {
        result.append(if (inputString[i] == 'z') 'a' else inputString[i] + 1)
        val halfNumber = (numbers[i] / 2.0).roundToInt()
        sumSoFar += halfNumber
        i++
    }

Kotlin

import kotlin.math.roundToInt

fun solution(inputString: String, numbers: List<Int>): String {
    val result = StringBuilder()
    var sumSoFar = 0
    var i = 0
    while (i < inputString.length && sumSoFar <= 20) {
        result.append(if (inputString[i] == 'z') 'a' else inputString[i] + 1)
        val halfNumber = (numbers[i] / 2.0).roundToInt()
        sumSoFar += halfNumber
        i++
    }
    result.reverse()
    val remainingNumbers = numbers.subList(i, numbers.size)
    val remainingNumbersString = remainingNumbers.joinToString(", ")
    return "$result $remainingNumbersString"
}

fun main() {
    val numbers = listOf(10, 20, 30, 50, 100)
    val result = solution("books", numbers)
    println(result)

    // Output:
    // ppc 50, 100
}

Kotlin

fun solution(inputString: String, numbers: List<Int>): String {
    var result = ""
    var sumSoFar = 0

Kotlin

import kotlin.math.roundToInt

fun solution(inputString: String, numbers: List<Int>): String {
    val result = StringBuilder()
    var sumSoFar = 0
    var i = 0
    while (i < inputString.length && sumSoFar <= 20) {
        result.append(if (inputString[i] == 'z') 'a' else inputString[i] + 1)
        val halfNumber = (numbers[i] / 2.0).roundToInt()
        sumSoFar += halfNumber
        i++
    }

Kotlin

import kotlin.math.roundToInt

fun solution(inputString: String, numbers: List<Int>): String {
    val result = StringBuilder()
    var sumSoFar = 0
    var i = 0
    while (i < inputString.length && sumSoFar <= 20) {
        result.append(if (inputString[i] == 'z') 'a' else inputString[i] + 1)
        val halfNumber = (numbers[i] / 2.0).roundToInt()
        sumSoFar += halfNumber
        i++
    }
    result.reverse()
    val remainingNumbers = numbers.subList(i, numbers.size)
    val remainingNumbersString = remainingNumbers.joinToString(", ")
    return "$result $remainingNumbersString"
}

fun main() {
    val numbers = listOf(10, 20, 30, 50, 100)
    val result = solution("books", numbers)
    println(result)

    // Output:
    // ppc 50, 100
}