Hackerrank - Super Reduced String

Hackerrank – Problem Statement

A description of the problem can be found on Hackerrank.

Solution

I created an accumulator with initial value as empty string. I iterated through each character and updated the accumulator

if an actual character is equals to last accumulator character, delete this character from the accumulator
else append the character to the accumulator

The result is the accumulator after the iteration.

I created solution in:

Scala
Java
JavaScript
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class SuperReducedString {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        String s = stdin.nextLine();
        String acc = "";
        for(int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if(acc.length() > 0 && acc.charAt(acc.length() - 1) == c) {
                acc = acc.substring(0, acc.length() - 1);
            } else {
                acc += c;
            }
        }
        System.out.println(acc.isEmpty() ? "Empty String" : acc);
        stdin.close();
    }
}

import java.util.*;

public class SuperReducedString {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

String s = stdin.nextLine();

String acc = "";

for(int i = 0; i < s.length(); i++) {

char c = s.charAt(i);

if(acc.length() > 0 && acc.charAt(acc.length() - 1) == c) {

acc = acc.substring(0, acc.length() - 1);

} else {

acc += c;

}

System.out.println(acc.isEmpty() ? "Empty String" : acc);

stdin.close();

}

JavaScript

'use strict';

const processData = input => {
    const line = input.split('\n')[0];
    let acc = "";
    for(let i = 0; i < line.length; i++) {
        const c = line[i];
        if(acc.length > 0 && acc[acc.length - 1] === c) {
            acc = acc.slice(0, acc.length - 1);
        } else {
            acc += c;
        }
    }
    console.log(acc.length === 0 ? "Empty String" : acc);
};

process.stdin.resume();
process.stdin.setEncoding("ascii");

let _input = "";
process.stdin.on("data", input => _input += input);
process.stdin.on("end", () => processData(_input));

'use strict';

const processData = input => {

const line = input.split('\n')[0];

let acc = "";

for(let i = 0; i < line.length; i++) {

const c = line[i];

if(acc.length > 0 && acc[acc.length - 1] === c) {

acc = acc.slice(0, acc.length - 1);

} else {

acc += c;

}

console.log(acc.length === 0 ? "Empty String" : acc);

};

process.stdin.resume();

process.stdin.setEncoding("ascii");

let _input = "";

process.stdin.on("data", input => _input += input);

process.stdin.on("end", () => processData(_input));

Scala

import scala.io.Source

object SuperReducedString extends App {
  val line = Source.stdin.getLines().toList.head
  val reduced = line.foldLeft("")(stringReduce)
  println(if(reduced.isEmpty) "Empty String" else reduced)

  def stringReduce(acc: String, c: Char): String = {
    if(acc.length > 0 && acc.charAt(acc.length - 1) == c) acc.substring(0, acc.length - 1) else acc + c
  }
}

import scala.io.Source

object SuperReducedString extends App {

val line = Source.stdin.getLines().toList.head

val reduced = line.foldLeft("")(stringReduce)

println(if(reduced.isEmpty) "Empty String" else reduced)

def stringReduce(acc: String, c: Char): String = {

if(acc.length > 0 && acc.charAt(acc.length - 1) == c) acc.substring(0, acc.length - 1) else acc + c

}

Ruby

s = gets.strip
acc = ""
for i in 0...(s.length) do
  c = s[i]
  if(acc.length > 0 && acc[acc.length - 1] == c)
    acc = acc.slice(0, acc.length - 1)
  else
    acc = acc + c
  end
end

if(acc.length == 0)
  puts "Empty String"
else
  puts acc
end

s = gets.strip

acc = ""

for i in 0...(s.length) do

c = s[i]

if(acc.length > 0 && acc[acc.length - 1] == c)

acc = acc.slice(0, acc.length - 1)

else

acc = acc + c

end

if(acc.length == 0)

puts "Empty String"

else

puts acc

end

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Super Reduced String