## DEV Community

Abhishek Chaudhary

Posted on

# Isomorphic Strings

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.

Example 1:

Input: s = "egg", t = "add"
Output: true

Example 2:

Input: s = "foo", t = "bar"
Output: false

Example 3:

Input: s = "paper", t = "title"
Output: true

Constraints:

• `1 <= s.length <= 5 * 104`
• `t.length == s.length`
• `s` and `t` consist of any valid ascii character.

SOLUTION:

``````class Solution:
def isIsomorphic(self, s: str, t: str) -> bool:
smap = {}
tmap = {}
slist = []
tlist = []
i = 0
for c in s:
if c not in smap:
smap[c] = i
i += 1
slist.append(smap[c])
i = 0
for c in t:
if c not in tmap:
tmap[c] = i
i += 1
tlist.append(tmap[c])
return slist == tlist
``````