205. Isomorphic Strings

QUESTION:

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.

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.

For example, Given `"egg"`, `"add"`, return true.

Given `"foo"`, `"bar"`, return false.

Given `"paper"`, `"title"`, return true.

Note: You may assume both s and t have the same length.

SOLUTION:

``````public class Solution {
public boolean isIsomorphic(String s, String t) {
Hashtable<Character, Character> reflectTable = new Hashtable<>();
for (int i = 0; i < s.length(); i++) {
char key = s.charAt(i);
Object value = reflectTable.get(key);
if (value == null) {
char tValue = t.charAt(i);
boolean containValue = reflectTable.containsValue(tValue);
if(containValue)
return false;
reflectTable.put(key, t.charAt(i));
} else {
if ((char) value != t.charAt(i))
return false;
}
}
return true;
}
}
``````