Pangrams Implementation in Java

Pangrams Implementation in Java

The sentence "The quick brown fox jumps over the lazy dog" contains every single letter in the alphabet. Such sentences are called pangrams.

import java.util.Scanner;

import java.util.TreeSet;

/**

 * 

 * 

 * @author xyz

 *

 */

public class PangramDetector {

/**

* Main method to execute the Pangram detector

* 

* @param args

*/

public static void main(String[] args) {

PangramDetector pangramDetector = new PangramDetector();

String line = null;

try{

Scanner userInput = new Scanner(System.in);

System.out.println("Please enter a sentence: ");

line = userInput.nextLine();

String missingLetters = pangramDetector.findMissingLetters(line);

System.out.println("Output:  \"" + missingLetters + "\"");

} catch (Exception e) {

System.out.println("Something is wrong: "+e.getMessage());

}

}

/**

* Find the missing letters from the user input. Time complexity for this

* method may go up to nlogn. I am ingnoring 26 alphabet letter as small number may not help to find complexity

* 

* @param sentence

* @return

*/

public String findMissingLetters(String sentence) {

final char[] alphabetArray = "abcdefghijklmnopqrstuvwxyz".toCharArray();

final TreeSet alphabetTreeSet = new TreeSet();

// Convert sentence to char array.

final char[] sentenceChar = sentence.toLowerCase().toCharArray();

// Keep a set of those chars that are present in sentence.

for (final char letter : sentenceChar) {

alphabetTreeSet.add(letter);

}

// Print the chars present in the alphabet but not in the user input.

final StringBuilder missingCharBuilder = new StringBuilder();

for (final char character : alphabetArray) {

if (!alphabetTreeSet.contains(character)) {

missingCharBuilder.append(character);

}

}

return missingCharBuilder.toString();

}

Output:

A)  "The quick brown fox jumps over the lazy dog"

Returns: ""

(This sentence contains every letter)

B)  "The slow purple oryx meanders past the quiescent canine"

Returns: "bfgjkvz"

C)  "We hates Bagginses!"

Returns: "cdfjklmopqruvxyz"