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
• Explanation: The strings s and t can be made identical by:
  Mapping ‘e’ to ‘a’.
  Mapping ‘g’ to ‘d’.
  

Example 2:

• Input: s = “foo”, t = “bar”
• Output: false
• Explanation: The strings s and t can not be made identical as ‘o’ needs to be mapped to both ‘a’ and ‘r’.

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.