Hackerrank - Kangaroo - Pavol Pidanič

Hackerrank – Problem Statement

A description of the problem can be found on Hackerrank.

Solution

There are two checks:

I checked if
$v_1$

is less then

$v_2$

and immediatelly print "NO". That means, kangaroo 1 would be never able to reach kangaroo 2.
I calculated differences between kangaroo positions
$x_d$

and their jumps

$v_d$

. If

$x_d % v_d == 0$

than kangaroo 1 will reach kangaroo 2. Else "NO".

I created solution in:

Scala
Java
JavaScript
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class Kangaroo {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int x1 = stdin.nextInt();
        int v1 = stdin.nextInt();
        int x2 = stdin.nextInt();
        int v2 = stdin.nextInt();

        System.out.println(isSameLocation(x1, v1, x2, v2));
        stdin.close();
    }

    private static String isSameLocation(int x1, int v1, int x2, int v2) {
        if(v1 < v2) return "NO";
        if(x1 < x2 && v1 > v2) {
            int xDiff = Math.abs(x1 - x2);
            int vDiff = Math.abs(v1 - v2);
            if(xDiff % vDiff == 0) {
                return "YES";
            } else {
                return "NO";
            }
        }
        return "NO";
    }
}

import java.util.*;

public class Kangaroo {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

int x1 = stdin.nextInt();

int v1 = stdin.nextInt();

int x2 = stdin.nextInt();

int v2 = stdin.nextInt();

System.out.println(isSameLocation(x1, v1, x2, v2));

stdin.close();

}

private static String isSameLocation(int x1, int v1, int x2, int v2) {

if(v1 < v2) return "NO";

if(x1 < x2 && v1 > v2) {

int xDiff = Math.abs(x1 - x2);

int vDiff = Math.abs(v1 - v2);

if(xDiff % vDiff == 0) {

return "YES";

} else {

return "NO";

}

return "NO";

}

JavaScript

'use strict';

const processData = input => {
    const lines = input.split('\n');
    const [x1, v1, x2, v2] = lines[0].split(' ').map(i => parseInt(i));
    console.log(sameLocation(x1, v1, x2, v2));
};

const sameLocation = (x1, v1, x2, v2) => {
    if(v1 < v2) return "NO";
    if(x1 < x2 && v1 > v2) {
        const xDiff = Math.abs(x1 - x2);
        const vDiff = Math.abs(v1 - v2);
        if(xDiff % vDiff == 0) {
            return "YES";
        } else {
            return "NO";
        }
    }
    return "NO";
};

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 [x1, v1, x2, v2] = lines[0].split(' ').map(i => parseInt(i));

console.log(sameLocation(x1, v1, x2, v2));

};

const sameLocation = (x1, v1, x2, v2) => {

if(v1 < v2) return "NO";

if(x1 < x2 && v1 > v2) {

const xDiff = Math.abs(x1 - x2);

const vDiff = Math.abs(v1 - v2);

if(xDiff % vDiff == 0) {

return "YES";

} else {

return "NO";

}

return "NO";

};

process.stdin.resume();

process.stdin.setEncoding("ascii");

let _input = "";

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

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

Scala

object Kangaroo extends App {
  val lines = Source.stdin.getLines().toList
  val numbers = lines.head.split(" ").map(_.toInt)
  val kangaroo1 = (numbers(0), numbers(1))
  val kangaroo2 = (numbers(2), numbers(3))

  println(if(sameLocation(kangaroo1, kangaroo2)) "YES" else "NO")

  def sameLocation(k1: (Int, Int), k2: (Int, Int)): Boolean = {
    val x1 = k1._1
    val x2 = k2._1
    val v1 = k1._2
    val v2 = k2._2
    if(v1 < v2) return false
    if(x1 < x2 && v1 > v2) {
      val xDiff = (x1 - x2).abs
      val vDiff = (v1 - v2).abs
      if(xDiff % vDiff == 0) {
        return true
      } else {
        return false
      }
    }
    false
  }
}

object Kangaroo extends App {

val lines = Source.stdin.getLines().toList

val numbers = lines.head.split(" ").map(_.toInt)

val kangaroo1 = (numbers(0), numbers(1))

val kangaroo2 = (numbers(2), numbers(3))

println(if(sameLocation(kangaroo1, kangaroo2)) "YES" else "NO")

def sameLocation(k1: (Int, Int), k2: (Int, Int)): Boolean = {

val x1 = k1._1

val x2 = k2._1

val v1 = k1._2

val v2 = k2._2

if(v1 < v2) return false

if(x1 < x2 && v1 > v2) {

val xDiff = (x1 - x2).abs

val vDiff = (v1 - v2).abs

if(xDiff % vDiff == 0) {

return true

} else {

return false

}

false

}

Ruby

def same_location(x1, v1, x2, v2)
  return "NO" if(v1 < v2)
  if(x1 < x2 && v1 > v2)
    xDiff = (x1 - x2).abs
    vDiff = (v1 - v2).abs
    if(xDiff % vDiff == 0)
      return "YES"
    else
      return "NO"
    end
  end
  "NO"
end

(x1, v1, x2, v2) = gets.strip.split(" ").map {|i| i.to_i}
puts same_location(x1, v1, x2, v2)

def same_location(x1, v1, x2, v2)

return "NO" if(v1 < v2)

if(x1 < x2 && v1 > v2)

xDiff = (x1 - x2).abs

vDiff = (v1 - v2).abs

if(xDiff % vDiff == 0)

return "YES"

else

return "NO"

end

"NO"

end

(x1, v1, x2, v2) = gets.strip.split(" ").map {|i| i.to_i}

puts same_location(x1, v1, x2, v2)

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Kangaroo

Hackerrank – Problem Statement

Solution

Java

JavaScript

Scala

Ruby

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