Given two strings s and t, determine if they are structurally identical (also known as isomorphic).

Two strings are structurally identical if the characters in s can be consistently replaced to form t, following these rules:

Each character in s must be consistently replaced with the same character in t.

The order of characters must be preserved.

No two different characters in s can map to the same character in t.

A character in s can map to itself in t.

Return true if such a mapping exists, otherwise return false.

Example 1:

Input: s = "door", t = "seen"
Output: true
Explanation: The mapping from s to t is consistent:
Mapping 'd' to 's'.
Mapping 'o' to 'e'.
Mapping 'r' to 'n'.

Example 2:

Input: s = "foo", t = "bar"
Output: false
Explanation:
The strings are not structurally identical because 'o' would need to map to both 'a' and 'r'.

Example 3:

Input: s = "light", t = "sound"
Output: true
Explanation: Valid mapping: l → s, i → o, g → u, h → n, t → d

Constraints

1 <= s.length <= 5 × 10⁴

t.length == s.length

s and t consist of valid ASCII characters (ASCII codes 1 through 127).

13. Structurally Identical Strings