Leetcode daily question (Python Implementation) 242- effective letter ectopic words

from 2022.6.19 From the beginning to the end of the autumn move , I will update... Every day At least one question leetcode I understand this blog On , Stick it up as evidence .

1 Code

class Solution:
def isAnagram(self, s, t):
from collections import defaultdict
s_dict = defaultdict(int)
t_dict = defaultdict(int)
for x in s:
s_dict[x] += 1
for x in t:
t_dict[x] += 1
return s_dict == t_dict

2 Understanding and explanation

This is me from leetcode An answer I saw , It's using collections Of defaultdict This container , and dict The difference is defaultdict This object contains a named default_factory Properties of , When constructing , The first parameter is used to provide the initial value for the attribute , The default is None. All other parameters （ Including keyword parameters ） Are equivalent to passing on to dict Constructor for

• We can test if dict It will appear keyerror This mistake
• My understanding is that for the first time s_dict[x] Will be initialized to {‘xxx’:0}（ because defaultdict(int) The parameter passed in is int） So it won't show up key error , Then count

3 Time and space complexity test

You can see that the time and space complexity are very good