Isomorphic Strings

Problem Statement

Given two strings s and t, determine if they are isomorphic.

Two strings are isomorphic if the characters in s can be replaced to get t, with the following conditions:

• 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.

Examples

Example 1:

Input:  s = "egg", t = "add"
Output: true
Explanation: 
Mapping 'e' to 'a' and 'g' to 'd' makes the strings identical.

Example 2:

Input:  s = "foo", t = "bar"
Output: false
Explanation: 
The character 'o' would need to map to both 'a' and 'r', which is not allowed.

Example 3:

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

Constraints

• 1 <= s.length <= 5 * 10^4
• t.length == s.length
• s and t consist of any valid ASCII character.

Code Template

class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:
        # Your code here
        pass

Solutions

• Solution 1: This approach uses a dictionary to map characters from s to t and a set to track already mapped characters in t. The time complexity is O(n) and space complexity is O(n).

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