Problem
Given two strings s and t, determine if they are isomorphic.
Two strings s and t are isomorphic if the characters in s can be replaced to get t.
All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character, but a character may map to itself.
Constraints
1 <= s.length <= 5 * 104
t.length == s.length
s and t consist of any valid ascii character.\
Thinking
-
Make a dictionary storing the mapping between s and t
-
Note: this is a one-to-one mapping, we need to check whethere the letter in t has been mapped or not
from typing import List
def isIsomorphic(s: str, t: str) -> bool:
if len(s) != len(t):
return False
letter_mapping = {}
letter_mapped = set()
for i in range(len(s)):
if s[i] not in letter_mapping:
if t[i] in letter_mapped:
return False
letter_mapping[s[i]] = t[i]
letter_mapped.add(t[i])
else:
if letter_mapping[s[i]] != t[i]:
return False
return True
if __name__ == "__main__":
print(isIsomorphic("egf", "aff"))
