S30 FAANMG Problem #14 - #16 | Hashing Problems

[sandy7907]

No description provided.

[super30admin]

Strengths:

• The solution correctly identifies anagrams by using a frequency array, which is a common and effective approach.
• The code is clear and easy to understand.
• The use of a hash map to group the anagrams is appropriate.

Areas for improvement:

1. Remove unnecessary imports (BigInteger) since they are not used.
2. Consider using computeIfAbsent to make the code more concise and avoid conditional checks for the map. For example:

   dict.computeIfAbsent(freqStr, k -> new ArrayList<>()).add(s);

3. The variable origStr is declared outside the loop. It is better to keep variables within the smallest scope possible. Using computeIfAbsent would eliminate the need for this variable.
4. Although not required, you might explore alternative key generation methods (like the prime number hash) to avoid string operations, which could be slightly faster in some cases. However, the current approach is perfectly acceptable.

Additionally, note that the problem requires grouping anagrams together, and your solution does that correctly. However, you included two other unrelated classes (IsomorphicString and WordPattern) in the same submission. For future exercises, please submit only the solution to the problem at hand to avoid confusion.

[super30admin]

Your solution for grouping anagrams is correct and efficient. Well done! Here are some suggestions to improve code clarity and efficiency:

1. Variable Naming: Consider renaming origStr to something more descriptive like anagramGroup or simply group. This makes the code easier to understand.

2. Simplify HashMap Update: Instead of using an if-else block to check if the key exists, you can use dict.computeIfAbsent to make the code more concise. For example:

   List<String> group = dict.computeIfAbsent(freqStr, k -> new ArrayList<>());
   group.add(s);

   This avoids the need for the conditional check and reduces code lines.

3. Remove Unused Imports: The import java.math.BigInteger is not used and can be removed to keep the code clean.

4. Consider Alternative Key Generation: While your method of using the frequency array string is correct, you might also consider using a string of characters representing the frequency counts (e.g., "Please review Day5! #1#2#0..." ) to avoid potential collisions in the string representation of the array? Actually, the array representation like "[0, 1, 2, ...]" is safe because it uniquely represents the counts. However, note that the string representation of an int array includes commas and spaces, which is fine but might be longer than necessary. Alternatively, you could build a key string by appending each count with a separator (e.g., using StringBuilder) to ensure uniqueness without extra characters. But your current method is acceptable.

Overall, your solution is correct and efficient. The suggestions are minor improvements for code quality.