Hackerrank - Beautiful Binary String

Hackerrank – Problem Statement

A description of the problem can be found on Hackerrank.

Solution

I replaced all occurences of "010" with an arbitrary placeholder. Then I counted the placeholders.

I created solution in:

Scala
Java
JavaScript
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class BeautifulBinaryString {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int l = Integer.parseInt(stdin.nextLine());
        String s = stdin.nextLine();
        String beautiful = s.replaceAll("010", "b");
        int changes = beautiful.replaceAll("[01]", "").length();
        System.out.println(changes);
        stdin.close();
    }
}

import java.util.*;

public class BeautifulBinaryString {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

int l = Integer.parseInt(stdin.nextLine());

String s = stdin.nextLine();

String beautiful = s.replaceAll("010", "b");

int changes = beautiful.replaceAll("[01]", "").length();

System.out.println(changes);

stdin.close();

}

JavaScript

'use strict';

const processData = input => {
    const lines = input.split('\n');
    const s = lines[1];
    const beautiful = s.replace(/010/g, "b");
    const changes = beautiful.replace(/[01]/g, "").length;
    console.log(changes);
};

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 lines = input.split('\n');

const s = lines[1];

const beautiful = s.replace(/010/g, "b");

const changes = beautiful.replace(/[01]/g, "").length;

console.log(changes);

};

process.stdin.resume();

process.stdin.setEncoding("ascii");

let _input = "";

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

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

Scala

object BeautifulBinaryString {

  def main(args: Array[String]) {
    val sc = new java.util.Scanner (System.in)
    val n = sc.nextInt()
    val B = sc.next()

    val beautiful = B.replaceAll("010", "b")
    val changes = beautiful.count(_ == 'b')
    println(changes)
  }
}

object BeautifulBinaryString {

def main(args: Array[String]) {

val sc = new java.util.Scanner (System.in)

val n = sc.nextInt()

val B = sc.next()

val beautiful = B.replaceAll("010", "b")

val changes = beautiful.count(_ == 'b')

println(changes)

}

Ruby

l = gets.to_i
s = gets.to_s.strip

s.gsub!(/010/, "b")
s.gsub!(/[01]/, "")
puts s.length()

l = gets.to_i

s = gets.to_s.strip

s.gsub!(/010/, "b")

s.gsub!(/[01]/, "")

puts s.length()

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Beautiful Binary String