isomorphic

Isomorphic strings

Description of the problem

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. For example, "egg" and "add" are isomorphic, but "foo" and "bar" are not.

Solution

The strategy to solve this problem is to keep a map of characters from s to t. The process scans each character in s, along with its counterpart in t:

1. When a character that has not been seen before in s is found, it is mapped to the corresponding character in t (the character in t in the same position).
2. But when a character that had already been seen before in s is found, the process checks that the previously mapped character is equal to the corresponding character in t. If the characters are equal, all is fine and the process continues. Otherwise, the process are not isomorphic.

If the entire string s is processed and both s and t have the same length, then they are isomorphic.

This implementation supports UTF-8 strings.