readme.md

Challenge: Anagram Grouping Challenge

Instructions

Create a function called anagramGrouping to use the HashTable class that we created. The function should take an array of words as input and return an array of arrays, where each inner array represents a group of anagrams.

Function Signature

/**
 * Groups anagrams from the input array of words using a HashTable.
 * @param {string[]} words - An array of words.
 * @returns {string[][]} - An array of arrays, each representing a group of anagrams.
 */
function anagramGrouping(words: string[]): string[][];

Examples

anagramGrouping(['listen', 'silent', 'hello', 'world', 'act', 'cat']);
// Output: [['listen', 'silent'], ['act', 'cat'], ['hello'], ['world']]

Hints

• You can use the provided HashTable class to implement efficient anagram grouping.
• Convert each word to a sorted string of characters to identify anagrams.
• For each sorted string, store anagrams in the HashTable with the sorted string as the key.

Solution

Click For Solution

const HashTable = require('./HashTable');

function anagramGrouping(words) {
  const anagramGroups = new HashTable();

  for (const word of words) {
    const sortedChars = word.split('').sort().join('');
    if (anagramGroups.get(sortedChars)) {
      anagramGroups.get(sortedChars).push(word);
    } else {
      anagramGroups.set(sortedChars, [word]);
    }
  }

  return anagramGroups.getValues();
}

module.exports = anagramGrouping;

Explanation

This is very similar to the anagram grouping where we used maps.

• Replace the Map with a HashTable to efficiently group anagrams.
• Iterate through each word in the input array and create a sorted version of the word's characters.
• This sorted string is used as a key in the HashTable. If the key already exists in the HashTable, we append the current word to the list of anagrams. If the key does not exist, we create a new entry in the HashTable with the key and an array containing the current word.
• After iterating through all the words, use the getValues method of the HashTable to obtain an array of arrays, where each inner array represents a group of anagrams.
• Return the array of anagram groups.

Test Cases

test('Grouping anagrams from an array of words', () => {
  const result1 = anagramGrouping([
    'listen',
    'silent',
    'hello',
    'world',
    'act',
    'cat',
  ]);
  expect(result1).toEqual(
    expect.arrayContaining([
      expect.arrayContaining(['listen', 'silent']),
      expect.arrayContaining(['act', 'cat']),
      expect.arrayContaining(['hello']),
      expect.arrayContaining(['world']),
    ])
  );
});