How to compare each char from the String with Keys from the HashMap?
I have used loops of course and change each Key to Char.
val romanNumbers = HashMap<String, Int>()
romanNumbers[""] = 0
romanNumbers["I"] = 1
romanNumbers["V"] = 5
Instead of string.get(i) I also tried string[i]
for (i in string.indices){
for ((k, v) in romanNumbers) {
if (string.length == 1) {
res1 = romanNumbers.getValue(string)
}
if (string.get(i) == k.single()) {
num1 = v
}
if (string[i + 1] == k.single()) {
num2 = v
}
}
}
error
Exception in thread "main" java.util.NoSuchElementException: Char sequence is empty.
at kotlin.text.StringsKt___StringsKt.single(_Strings.kt:223)
at CodeWars.MappingTrainingKt.decode(MappingTraining.kt:38)
at CodeWars.MappingTrainingKt.main(MappingTraining.kt:4)
at CodeWars.MappingTrainingKt.main(MappingTraining.kt)
Related
I'm working on Splay Tree. I have a lot of command input (add, delete and etc), Hence the output is also huge (32MB of text in a txt file)
I have a memory problem, I am currently using two MultitableList and I have 200 MB of virtual memory (128 MB is needed for the project)
I run on Linux with the command:
$ kotlinc Kotlin.kt -include-runtime -d outPutFile.jar
$ /usr/bin/time -v java -jar outPutFile.jar
result: Maximum resident set size (kbytes): 249732 (With each launch different sizes but about 200)
how can i reduce the size? I need to change the size after each cycle
class SplayTree {
var ROOT: Node? = null
class Node(val key: Long, var value: String?) {
var _parent: SplayTree.Node? = null
var _RightChild: SplayTree.Node? = null
var _LeftChild: SplayTree.Node? = null
... there is a code here ...
// for output
override fun toString(): String {
if (_parent == null) {
return "[${key} ${value}]"
} else {
return "[${key} ${value} ${_parent!!.key}]"
}
}
}
... there is a code here ...
override fun toString(): String {
if (ROOT == null) {
return "_"
}
println(ROOT)
var NOWqueueList: List<Node?> = listOf(ROOT)
var BABYqueue: MutableList<Node?> = MutableList(0) { null }
//var NOWqueueList = Array<Node?>(1, {ROOT}) // Array
//var BABYqueue = Array<Node?>(1, {null}) // Array
//var n = 1 // Array
for (h in 1 until height(ROOT)) {
// for Array
//var pos = -1
//n *= 2
//BABYqueue = Array<Node?>(n, {null}) //for future line
for (ROOTList in NOWqueueList) {
//pos++ // Array
if ( ROOTList != null){
//left
if (ROOTList.haveLeftBaby()) {
//BABYqueue[pos] = ROOTList._LeftChild // Array
BABYqueue.add(ROOTList._LeftChild)
print(ROOTList._LeftChild.toString())
print(" ")
} else {
//BABYqueue[pos] = null // Array
BABYqueue.add(null)
print("_ ")
}
//pos++ // Array
//right
if (ROOTList.haveRightBaby()) {
//BABYqueue[pos] = ROOTList._RightChild // Array
BABYqueue.add(ROOTList._RightChild)
print(ROOTList._RightChild.toString())
print(" ")
} else {
//BABYqueue[pos] = null
BABYqueue.add(null)
print("_ ")
}
} else{ //если пустой то + 2 "_"
//BABYqueue[pos] = null // Array
//pos++ // Array
//BABYqueue[pos] = null // Array
BABYqueue.add(null)
BABYqueue.add(null)
print("_ _ ")
}
}
//NOWqueueList.clear() //worked when was MultitableList
NOWqueueList = BABYqueue.toList() // equate
//NOWqueueList = BABYqueue.clone() // Array
//println(NOWqueueList.joinToString(" ")) // вывожу готовый
println()
BABYqueue.clear()
}
//NOWqueueList.clear()
BABYqueue.clear()
return " end="
}
}
fun main() {
... there is a code here ...
}
I tried using Array, it still came out as with MultitableList
I can't solve this problem, how to separate the numbers and do the required arithmetic
https://codeforces.com/group/MWSDmqGsZm/contest/219158/problem/O
This is my code , I don't know how true it is
fun main(args:Array<String>) {
val scanner = Scanner(System.`in`)
var s: String = read()!!
var c: Char? = null
var a: String = ""
var b: String = ""
var t: Boolean = true
for (i in 1..s.length) {
if (s[i] == '+' || s[i] == '-' || s[i] == '*' || s[i] == '/') {
c = s[i]
t = false
}else{
if(t){
a+=s[i]
}else{
b+=s[i]
}
}
}
if(c=='+'){
println(a+b)
}else if (c=='-'){
println( "$a - $b" )
}else if (c=='*'){
println("$a * $b")
}else{
println("$a / $b")
}
Try this code:
fun main() {
val str = readLine()!!
val (index, operator) = str.findAnyOf(listOf("+", "-", "*", "/"))!!
val a = str.substring(0, index).toInt()
val b = str.substring(index + 1).toInt()
val result = when (operator) {
"+" -> a + b
"-" -> a - b
"*" -> a * b
"/" -> a / b
else -> -1
}
println(result)
}
findAnyOf documentation:
Finds the first occurrence of any of the specified [strings] in this char sequence.
Returns A pair of an index of the first occurrence of matched string from [strings] and the string matched or null if none of [strings] are found.
Rest of the logic is quite straightforward.
/**
* Example:
* var li = ListNode(5)
* var v = li.`val`
* Definition for singly-linked list.
* class ListNode(var `val`: Int) {
* var next: ListNode? = null
* }
*/
class Solution {
fun mergeTwoLists(l1: ListNode?, l2: ListNode?): ListNode? {
var head : ListNode?
var tail: ListNode?
var firstPointer : ListNode? = l1
var secondPointer : ListNode? = l2
while( firstPointer != null || secondPointer != null){
var next : ListNode?
if (firstPointer == null || secondPointer == null){
if (secondPointer != null){
next.val = secondPointer.val
secondPointer = secondPointer.next
}else {
next.val = firstPointer.val
firstPointer = firstPointer.next
}
}else if(firstPointer.val <= secondPointer.val) {
next.val = firstPointer.val
firstPointer = firstPointer.next
}else if(secondPointer.val <= firstPointer.val ){
next.val = secondPointer.val
secondPointer = secondPointer.next
}
if (head == null){
head = next
tail = next
}else {
tail.next = next
tail = next
}
}
return head
}
}
getting a lot of compile time errors
Line 22: Char 29: error: expecting property name or receiver type
next.val = secondPointer.val
^
Line 25: Char 29: error: expecting property name or receiver type
next.val = firstPointer.val
^
Line 28: Char 39: error: type expected
}else if(firstPointer.val <= secondPointer.val) {
^
val is a keyword in kotlin. If you want to use it as a name of a field, you need to wrap it into backticks: secondPointer.`val`, firstPointer.`val` (actualy, code example in the comment before your code shows that).
Well, I don't know Kotlin well, but from my perspective this might be the problem:
var next : ListNode?
Because you define a variable, but it is still null.
When you then try to access its field val you can't, because null has no such field.
I'm struggling with types with my program, I've been asked to do it in JS first and it worked fine but now I can't achieve the result.
Do you think I should make another 'algorithm' ? In advance, thank you for your time.
fun main(){
// the idea is to put numbers in a box
// that cant be larger than 10
val data = "12493419133"
var result = data[0]
var currentBox = Character.getNumericValue(data[0])
var i = 1
while(i < data.length){
val currentArticle = Character.getNumericValue(data[i])
currentBox += currentArticle
println(currentBox)
if(currentBox <= 10){
result += Character.getNumericValue(currentArticle)
}else{
result += '/'
//var resultChar = result.toChar()
// result += '/'
currentBox = Character.getNumericValue(currentArticle)
result += currentArticle
}
i++
}
print(result) //should print 124/9/341/91/33
}
The result is actually of a Char type, and the overload operator function + only accepts Int to increment ASCII value to get new Char.
public operator fun plus(other: Int): Char
In idomatic Kotlin way, you can solve your problem:
fun main() {
val data = "12493419133"
var counter = 0
val result = data.asSequence()
.map(Character::getNumericValue)
.map { c ->
counter += c
if (counter <= 10) c.toString() else "/$c".also{ counter = c }
}
.joinToString("") // terminal operation, will trigger the map functions
println(result)
}
Edit: If the data is too large, you may want to use StringBuilder because it doesn't create string every single time the character is iterated, and instead of using a counter of yourself you can use list.fold()
fun main() {
val data = "12493419133"
val sb = StringBuilder()
data.fold(0) { acc, c ->
val num = Character.getNumericValue(c)
val count = num + acc
val ret = if (count > 10) num.also { sb.append('/') } else count
ret.also { sb.append(c) } // `ret` returned to ^fold, next time will be passed as acc
}
println(sb.toString())
}
If you want a result in List<Char> type:
val data = "12493419133"
val result = mutableListOf<Char>()
var sum = 0
data.asSequence().forEach {
val v = Character.getNumericValue(it)
sum += v
if (sum > 10) {
result.add('/')
sum = v
}
result.add(it)
}
println(result.joinToString(""))
The program works, however, I still get a logical error: the final letter doesn't run through. For example, when I enter aaaabbbbccccdddd the output I get is a4b4c4 but there is no d4.
fun main () {
val strUser = readLine()!!.toLowerCase()
val iLength = strUser!!.length
var iMatch : Int = 0
var chrMatch : Char = strUser[0]
for (i in 0..iLength) {
if (strUser[i] == chrMatch) {
iMatch += 1
}else {
print("$chrMatch$iMatch")
chrMatch = strUser[i]
iMatch = 1
}
}
}
There are many solutions, but the best is RegExp
fun encode(input: String): String =
input.replace(Regex("(.)\\1*")) {
String.format("%d%s", it.value.length, it.groupValues[1])
}
demo
Test result
println(encode("aaaabbbbccccdddd")) // 4a4b4c4d
strUser contains chars by indexes from 0 to iLength - 1 so you have to write for (i in 0 until iLength) instead of for (i in 0..iLength)
But Tenfour04 is completely right, you can just iterate strUser without indexes:
fun main() {
val strUser = readLine()!!.toLowerCase()
var iMatch: Int = 0
var chrMatch: Char = strUser[0]
for (char in strUser) {
if (char == chrMatch) {
iMatch += 1
} else {
print("$chrMatch$iMatch")
chrMatch = char
iMatch = 1
}
}
}
fun main () {
val strUser = readLine()!!.toLowerCase()
var iMatch : Int = 0
var chrMatch : Char = strUser[0]
for (char in strUser+1) {
if (char == chrMatch) {
iMatch += 1
}else {
print("$chrMatch$iMatch")
chrMatch = char
iMatch = 1
}
}
}
fun runLengthEncoding(inputString: String): String {
val n=inputString.length
var i : Int =0
var result : String =""
while(i<n){
var count =1
while(i<n-1 && inputString[i] == inputString[i+1]){
count ++
i++
}
result=result.toString()+count.toString()+inputString[i].toString()
i++
}
return result
}