Hackerrank - Game of Thrones - I

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

Solution
Palindrome is when:

if the length of a string is even, then each character needs to be even times in the string
if the length of a string is odd, then there is only one character, which count in the string is odd

I created solution in:

Java
JavaScript
Scala
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class GameOfThrones1 {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        String line = stdin.nextLine();
        Map<Character, Integer> charMap = new HashMap<>();
        for(int i = 0; i < line.length(); i++) {
            char c = line.charAt(i);
            int count = charMap.getOrDefault(c, 0);
            charMap.put(c, count + 1);
        }
        System.out.println(isPalindrome(line.length(), charMap));
        stdin.close();
    }

    private static String isPalindrome(int length, Map<Character, Integer> charMap) {
        boolean isPalindrome = true;
        if(length % 2 == 0) {
            for(char key : charMap.keySet()) {
                if(charMap.get(key) % 2 != 0) {
                    isPalindrome = false;
                    break;
                }
            }
        }
        if(length % 2 != 0) {
            int oddCount = 0;
            for(char key : charMap.keySet()) {
                if(charMap.get(key) % 2 != 0) {
                    oddCount++;
                }
            }
            isPalindrome = oddCount == 1;
        }
        if(isPalindrome) {
            return "YES";
        } else {
            return "NO";
        }
    }
}

import java.util.*;

public class GameOfThrones1 {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

String line = stdin.nextLine();

Map<Character, Integer> charMap = new HashMap<>();

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

char c = line.charAt(i);

int count = charMap.getOrDefault(c, 0);

charMap.put(c, count + 1);

}

System.out.println(isPalindrome(line.length(), charMap));

stdin.close();

}

private static String isPalindrome(int length, Map<Character, Integer> charMap) {

boolean isPalindrome = true;

if(length % 2 == 0) {

for(char key : charMap.keySet()) {

if(charMap.get(key) % 2 != 0) {

isPalindrome = false;

break;

}

if(length % 2 != 0) {

int oddCount = 0;

for(char key : charMap.keySet()) {

if(charMap.get(key) % 2 != 0) {

oddCount++;

}

isPalindrome = oddCount == 1;

}

if(isPalindrome) {

return "YES";

} else {

return "NO";

}

JavaScript

'use strict';

let isPalindrome = (length, charMap) => {
    let isPalindrome = true;
    if(length % 2 == 0) {
        for(let prop in charMap) {
            if(charMap.hasOwnProperty(prop) && charMap[prop] % 2 !== 0) {
                isPalindrome = false;
                break;
            }
        }
    }
    if(length % 2 != 0) {
        let oddCount = 0;
        for(let prop in charMap) {
            if(charMap[prop] % 2 !== 0) {
                oddCount++;
            }
        }
        isPalindrome = oddCount === 1;
    }
    if(isPalindrome) {
        return "YES";
    } else {
        return "NO";
    }
};

const processData = input => {
    let charMap = {};
    for(let i = 0; i < input.length; i++) {
        let count = charMap[input[i]];
        if(count) {
            charMap[input[i]] = count + 1;
        } else {
            charMap[input[i]] = 1;
        }
    }
    console.log(isPalindrome(input.length, charMap));
};

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 isPalindrome = (length, charMap) => {

let isPalindrome = true;

if(length % 2 == 0) {

for(let prop in charMap) {

if(charMap.hasOwnProperty(prop) && charMap[prop] % 2 !== 0) {

isPalindrome = false;

break;

}

if(length % 2 != 0) {

let oddCount = 0;

for(let prop in charMap) {

if(charMap[prop] % 2 !== 0) {

oddCount++;

}

isPalindrome = oddCount === 1;

}

if(isPalindrome) {

return "YES";

} else {

return "NO";

}

};

const processData = input => {

let charMap = {};

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

let count = charMap[input[i]];

if(count) {

charMap[input[i]] = count + 1;

} else {

charMap[input[i]] = 1;

}

console.log(isPalindrome(input.length, charMap));

};

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 GameOfThrones1 extends App {
  val line = Source.stdin.bufferedReader().readLine()
  validate(line)

  def isPalindrome(length: Int, charMap: Map[Char, String]): Boolean = {
    if(length % 2 == 0)
      charMap.forall(entry => entry._2.length % 2 == 0)
    else
      charMap.count(entry => entry._2.length % 2 == 1) == 1
  }

  def validate(line: String): Unit = {
    val charMap = line.groupBy(c => c)
    println(if(isPalindrome(line.length, charMap)) "YES" else "NO")
  }
}

import scala.io.Source

object GameOfThrones1 extends App {

val line = Source.stdin.bufferedReader().readLine()

validate(line)

def isPalindrome(length: Int, charMap: Map[Char, String]): Boolean = {

if(length % 2 == 0)

charMap.forall(entry => entry._2.length % 2 == 0)

else

charMap.count(entry => entry._2.length % 2 == 1) == 1

}

def validate(line: String): Unit = {

val charMap = line.groupBy(c => c)

println(if(isPalindrome(line.length, charMap)) "YES" else "NO")

}

Ruby

def can_be_palindrome(input)
  char_hash = Hash.new(0)
  input.each_char { |c| char_hash[c] += 1 }
  
  if input.length.even?
    char_hash.each_key { |key| return 0 if char_hash[key].odd? }
  else
    has_odd = false
    char_hash.each_key do |key| 
      return 0 if has_odd && char_hash[key].odd?
      has_odd = true if char_hash[key].odd?
    end
  end
  return 1
end

string = gets.chomp 

found = can_be_palindrome(string)

if found == 1
    puts "YES"
else
    puts "NO"
end

def can_be_palindrome(input)

char_hash = Hash.new(0)

input.each_char { |c| char_hash[c] += 1 }

if input.length.even?

char_hash.each_key { |key| return 0 if char_hash[key].odd? }

else

has_odd = false

char_hash.each_key do |key|

return 0 if has_odd && char_hash[key].odd?

has_odd = true if char_hash[key].odd?

end

return 1

end

string = gets.chomp

found = can_be_palindrome(string)

if found == 1

puts "YES"

else

puts "NO"

end

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Game of Thrones – I