Pavol Pidanič

Hackerrank – Compute the Area of a Polygon

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution Create matrices of point pairs as follows

|x1 x2|
|y1 y2|

1 2	\|x1 x2\| \|y1 y2\|

|x2 x3|
|y2 y3|

1 2	\|x2 x3\| \|y2 y3\|

… Calculate the determinat of each matrix: x1 * y2 – x2 * y1 And sum the determinants. In the end divide the sum with 2. Solution based on this. I […]

Hackerrank – Remove Duplicates

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution I created solution in: Scala All solutions are also available on my GitHub. Scala

object RemoveDuplicates extends App {
  println(Console.readLine.distinct)
}

object RemoveDuplicates extends App {

println(Console.readLine.distinct)

}

Hackerrank – Lambda Calculus – Reductions #4

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution I created solution in: Plain Text All solutions are also available on my GitHub. Plain Text

CAN'T REDUCE

1	CAN'T REDUCE

Hackerrank – Lambda Calculus – Reductions #3

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution I created solution in: Plain Text All solutions are also available on my GitHub. Plain Text

CAN'T REDUCE

1	CAN'T REDUCE

Hackerrank – Lambda Calculus – Reductions #2

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution I created solution in: Plain Text All solutions are also available on my GitHub. Plain Text

w

Hackerrank – Lambda Calculus – Reductions #1

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution I created solution in: Plain Text All solutions are also available on my GitHub. Plain Text

y

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 […]

Hackerrank – Jumping on the Clouds

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution I created a pointer for an actual position which starts at index 0. I always tried to jump at position i + 2. If it is not possible because of thundercloud I step at i + 1 position. I do […]

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()

Hackerrank – Circular Array Rotation

Hackerrank – Problem Statement A description of the problem can be found on Hackerrank. Solution We rotate the array in circles. That why it is enough to calculate a position after all rotations using modulo. We split the array into two halves at position array_length – calculated_position. We change halves and concat them – the […]