class Solution:
def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
"""
Groups an array of strings into lists of anagrams.
Parameters:
strs (List[str]): List of strings to be grouped.
Returns:
List[List[str]]: A list where each sublist contains anagrams grouped together.
"""
anagrams = {} # Dictionary to hold groups of anagrams, key is sorted tuple of the string
# Iterate over each string in the input list
for s in strs:
# Sort the string and convert to tuple to use as a hashable key
key = tuple(sorted(s))
# If the key exists in the dictionary, append the current string to the group.
if key in anagrams:
anagrams[key].append(s)
else:
# Create a new group for this key with the current string.
anagrams[key] = [s]
# Return all the grouped anagrams as a list of lists.
return list(anagrams.values())
Summary of Techniques and Approaches:
Hashing with Sorted Keys: The solution sorts each string and uses it as a tuple key in a dictionary. This method is applicable to grouping or matching problems where the order of characters (or elements) is irrelevant.
Dictionary for Aggregation: Using a dictionary to store and group similar items is a common approach in data processing tasks, especially where grouping by a computed key is needed.
Time Complexity Consideration: Although sorting each string introduces extra computation, this approach remains efficient given the problem constraints and guarantees that anagrams yield the same key.
General Applicability: These techniques can be employed in various problems that require grouping or classifying items. Look for problems where you can transform elements into a standardized form (such as sorting or normalization) to easily compare them.