Hackerrank - The Love-Letter Mystery

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

Solution
For an element at index i create sum of differences between an ordinal number of character at index length(s)-i-1 and an ordinal number of the character at index i.

I created solution in:

Java
Ruby
JavaScript
Scala

All solutions are also available on my GitHub.

Java

import java.util.Scanner;

public class LoveLetterMystery {
    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int tests = stdin.nextInt();
        for(int i = 0; i < tests; i++) {
            String s = stdin.next();
            int diff = 0;
            for(int j = 0; j < s.length() / 2; j++) {
                diff += Math.abs(Character.codePointAt(s, j) - Character.codePointAt(s, s.length() - j - 1));
            }
            System.out.println(diff);
        }
        stdin.close();
    }
}

import java.util.Scanner;

public class LoveLetterMystery {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

int tests = stdin.nextInt();

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

String s = stdin.next();

int diff = 0;

for(int j = 0; j < s.length() / 2; j++) {

diff += Math.abs(Character.codePointAt(s, j) - Character.codePointAt(s, s.length() - j - 1));

}

System.out.println(diff);

}

stdin.close();

}

Ruby

tests = gets.chomp.to_i
tests.times do
  input = gets.chomp
  changes = 0
  for i in 0...input.length / 2
    char_front = input[i]
    char_back = input[input.length - 1 - i]
    diff = (char_front.ord - char_back.ord).abs
    changes += diff
  end
  puts changes
end

tests = gets.chomp.to_i

tests.times do

input = gets.chomp

changes = 0

for i in 0...input.length / 2

char_front = input[i]

char_back = input[input.length - 1 - i]

diff = (char_front.ord - char_back.ord).abs

changes += diff

end

puts changes

end

JavaScript

function processData(input) {
    var lines = input.split('\n');
    for(var i = 1; i < lines.length; i++) {
        var diff = 0;
        for(var j = 0; j < lines[i].length / 2; j++) {
            diff += Math.abs(lines[i].charCodeAt(j) - lines[i].charCodeAt(lines[i].length - j - 1));
        }
        console.log(diff);
    }
}

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
    processData(_input);
});

function processData(input) {

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

for(var i = 1; i < lines.length; i++) {

var diff = 0;

for(var j = 0; j < lines[i].length / 2; j++) {

diff += Math.abs(lines[i].charCodeAt(j) - lines[i].charCodeAt(lines[i].length - j - 1));

}

console.log(diff);

}

process.stdin.resume();

process.stdin.setEncoding("ascii");

_input = "";

process.stdin.on("data", function (input) {

_input += input;

});

process.stdin.on("end", function () {

processData(_input);

});

Scala

import scala.io.Source

object TheLoveLetterMystery extends App {
  val lines = Source.stdin.getLines().drop(1)
  val diffs = lines.map(changes)
  println(diffs.mkString("\n"))

  def changes(s: String): Int = {
    val halves = s.splitAt(s.length / 2)
    val reverted2 = halves._2.reverse
    halves._1.indices.map(i => ordinalDiff(halves._1.charAt(i), reverted2.charAt(i))).sum
  }

  def ordinalDiff(ch1: Char, ch2: Char): Int = {
    (ch2 - ch1).abs
  }
}

import scala.io.Source

object TheLoveLetterMystery extends App {

val lines = Source.stdin.getLines().drop(1)

val diffs = lines.map(changes)

println(diffs.mkString("\n"))

def changes(s: String): Int = {

val halves = s.splitAt(s.length / 2)

val reverted2 = halves._2.reverse

halves._1.indices.map(i => ordinalDiff(halves._1.charAt(i), reverted2.charAt(i))).sum

}

def ordinalDiff(ch1: Char, ch2: Char): Int = {

(ch2 - ch1).abs

}

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – The Love-Letter Mystery