Update maximum-length-of-a-concatenated-string-with-unique-characters.py

Author: kamyu104

Python/maximum-length-of-a-concatenated-string-with-unique-characters.py

@@ -1,5 +1,5 @@
 # Time:  O(n) ~ O(2^n)
-# Space: O(2^n)
+# Space: O(1) ~ O(2^n)
 
 power = [1]
 log2 = {1:0}