feature: group anagrams reduce revisit

solairerove · Dec 8, 2023 · c4e5da2 · c4e5da2
1 parent 29b8132
commit c4e5da2
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/arrays/GroupAnagrams.py b/arrays/GroupAnagrams.py
@@ -1,8 +1,9 @@
 import collections
+from functools import reduce
 from typing import List
 
 
-# O(w * n * log(n)) time || O(wn) space
+# O(w * n * log(n)) time || O(w * n) space
 def group_anagrams(self, strs: List[str]) -> List[List[str]]:
     dic = collections.defaultdict(list)
 
@@ -12,6 +13,11 @@ def group_anagrams(self, strs: List[str]) -> List[List[str]]:
     return list(dic.values())
 
 
+# O(w * n * log(n)) time || O(w * n) space
+def group_anagrams_reduce(self, strs: List[str]) -> List[List[str]]:
+    return list(reduce(lambda acc, s: acc[tuple(sorted(s))].append(s) or acc, strs, collections.defaultdict(list)).values())
+
+
 # O(n * m) time || O(n * m) space,
 # m - number of strings
 # n - average number of letters

diff --git a/arrays/test/test_group_anagrams.py b/arrays/test/test_group_anagrams.py
@@ -1,6 +1,6 @@
 import unittest
 
-from arrays.GroupAnagrams import group_anagrams, group_anagrams_count_approach
+from arrays.GroupAnagrams import group_anagrams, group_anagrams_count_approach, group_anagrams_reduce
 
 
 class MyTestCase(unittest.TestCase):
@@ -11,6 +11,9 @@ def test_group_anagrams(self):
         self.assertEqual([['eat', 'tea', 'ate'], ['tan', 'nat'], ['bat']],
                          group_anagrams_count_approach(self, ["eat", "tea", "tan", "ate", "nat", "bat"]))
 
+        self.assertEqual([['eat', 'tea', 'ate'], ['tan', 'nat'], ['bat']],
+                         group_anagrams_reduce(self, ["eat", "tea", "tan", "ate", "nat", "bat"]))
+
 
 if __name__ == '__main__':
     unittest.main()