Hackerrank - Two Arrays - Pavol Pidanič

Problem Statement
A description of the problem can be found on Hackerrank.

Solution
Sort two arrays. array1 ascending, array2 descending. Add each i^th element in both array and compare if their sum is greater or equals than required amount.

I created solution in:

Java
JavaScript
Scala
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class TwoArrays {

    private static class Descending implements Comparator<Integer> {
        @Override
        public int compare(Integer i, Integer j) {
            return j - i;
        }
    }

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int tests = stdin.nextInt();
        for(int i = 0; i < tests; i++) {
            int n = stdin.nextInt();
            int sum = stdin.nextInt();
            Integer[] array1 = new Integer[n];
            Integer[] array2 = new Integer[n];
            for(int j = 0; j < n; j++){
                array1[j] = stdin.nextInt();
            }
            for(int j = 0; j < n; j++){
                array2[j] = stdin.nextInt();
            }
            Arrays.sort(array1);
            Arrays.sort(array2, new Descending());
            System.out.println(isCorrect(array1, array2, sum));
        }
        stdin.close();
    }

    private static String isCorrect(Integer[] array1, Integer[] array2, int sum) {
        for(int i = 0; i < array1.length; i++) {
            if(array1[i] + array2[i] < sum) {
                return "NO";
            }
        }
        return "YES";
    }
}

import java.util.*;

public class TwoArrays {

private static class Descending implements Comparator<Integer> {

@Override

public int compare(Integer i, Integer j) {

return j - i;

}

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

int tests = stdin.nextInt();

for(int i = 0; i < tests; i++) {

int n = stdin.nextInt();

int sum = stdin.nextInt();

Integer[] array1 = new Integer[n];

Integer[] array2 = new Integer[n];

for(int j = 0; j < n; j++){

array1[j] = stdin.nextInt();

}

for(int j = 0; j < n; j++){

array2[j] = stdin.nextInt();

}

Arrays.sort(array1);

Arrays.sort(array2, new Descending());

System.out.println(isCorrect(array1, array2, sum));

}

stdin.close();

}

private static String isCorrect(Integer[] array1, Integer[] array2, int sum) {

for(int i = 0; i < array1.length; i++) {

if(array1[i] + array2[i] < sum) {

return "NO";

}

return "YES";

}

JavaScript

'use strict';

let isCorrect = (arr1, arr2, sum) => {
    for(let i = 0; i < arr1.length; i++) {
        if(arr1[i] + arr2[i] < sum) {
            return "NO";
        }
    }
    return "YES";
};

const processData = input => {
    let lines = input.split('\n');
    let tests = parseInt(lines[0]);
    let index = 1;
    for(let i = 0; i < tests; i++) {
        let def = lines[index++].split(' ').map(i => parseInt(i));
        let n = def[0];
        let sum = def[1];
        let arr1 = lines[index++].split(' ').map(i => parseInt(i)).sort((i, j) => i - j);
        let arr2 = lines[index++].split(' ').map(i => parseInt(i)).sort((i, j) => j - i);
        console.log(isCorrect(arr1, arr2, sum));
    }
};

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

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

'use strict';

let isCorrect = (arr1, arr2, sum) => {

for(let i = 0; i < arr1.length; i++) {

if(arr1[i] + arr2[i] < sum) {

return "NO";

}

return "YES";

};

const processData = input => {

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

let tests = parseInt(lines[0]);

let index = 1;

for(let i = 0; i < tests; i++) {

let def = lines[index++].split(' ').map(i => parseInt(i));

let n = def[0];

let sum = def[1];

let arr1 = lines[index++].split(' ').map(i => parseInt(i)).sort((i, j) => i - j);

let arr2 = lines[index++].split(' ').map(i => parseInt(i)).sort((i, j) => j - i);

console.log(isCorrect(arr1, arr2, sum));

}

};

process.stdin.resume();

process.stdin.setEncoding("ascii");

var _input = "";

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

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

Scala

import scala.io.Source

object TwoArrays extends App {
  val console = Source.stdin.bufferedReader()
  val tests = console.readLine().toInt
  val descendingSort = (i: Int, j: Int) => i > j
  (0 until tests).foreach(i => {
    val line = console.readLine()
    val numbers = line.split(" ").map(_.toInt)
    val n = numbers(0)
    val sum = numbers(1)
    val array1 = console.readLine().split(" ").map(_.toInt)
    val array2 = console.readLine().split(" ").map(_.toInt)
    val sortedArray1 = array1.sorted
    val sortedArray2 = array2.sortWith(descendingSort)
    println(prove(sortedArray1, sortedArray2, sum))
  })

  def prove(arr1: Array[Int], arr2: Array[Int], sum: Int): String = {
    val correct = arr1.indices.forall(i => {arr1(i) + arr2(i) >= sum})
    if(correct)
      "YES"
    else
      "NO"
  }
}

import scala.io.Source

object TwoArrays extends App {

val console = Source.stdin.bufferedReader()

val tests = console.readLine().toInt

val descendingSort = (i: Int, j: Int) => i > j

(0 until tests).foreach(i => {

val line = console.readLine()

val numbers = line.split(" ").map(_.toInt)

val n = numbers(0)

val sum = numbers(1)

val array1 = console.readLine().split(" ").map(_.toInt)

val array2 = console.readLine().split(" ").map(_.toInt)

val sortedArray1 = array1.sorted

val sortedArray2 = array2.sortWith(descendingSort)

println(prove(sortedArray1, sortedArray2, sum))

})

def prove(arr1: Array[Int], arr2: Array[Int], sum: Int): String = {

val correct = arr1.indices.forall(i => {arr1(i) + arr2(i) >= sum})

if(correct)

"YES"

else

"NO"

}

Ruby

def prove(arr1, arr2, sum)
  for i in 0..arr1.length - 1 do
    return "NO" if arr1[i] + arr2[i] < sum
  end
  return "YES"
end

test_cases = gets.chomp.to_i
test_cases.times do
  (arr_length, sum) = gets.chomp.split.map { |e| e.to_i}
  arr1 = gets.chomp.split.map { |e| e.to_i}
  arr2 = gets.chomp.split.map { |e| e.to_i}
  arr1.sort! {|i, j| i <=> j}
  arr2.sort! { |i, j| j <=> i}
  puts prove(arr1, arr2, sum)
end

def prove(arr1, arr2, sum)

for i in 0..arr1.length - 1 do

return "NO" if arr1[i] + arr2[i] < sum

end

return "YES"

end

test_cases = gets.chomp.to_i

test_cases.times do

(arr_length, sum) = gets.chomp.split.map { |e| e.to_i}

arr1 = gets.chomp.split.map { |e| e.to_i}

arr2 = gets.chomp.split.map { |e| e.to_i}

arr1.sort! {|i, j| i <=> j}

arr2.sort! { |i, j| j <=> i}

puts prove(arr1, arr2, sum)

end

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Two Arrays