# Isomorphic Strings

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.

## Code

``````public class Solution {
boolean isIsomorphic(char[] S, char[] T) {
char[] MAP = new char;
for(int i = 0; i < S.length; i++) {
if(MAP[(int)S[i]] == 0) {
// not mapped
MAP[(int)S[i]] = T[i];
} else {
if ( MAP[(int)S[i]] != T[i]) {
return false;
}
}
}

return true;
}

public boolean isIsomorphic(String s, String t) {

char[] S = s.toCharArray();
char[] T = t.toCharArray();

if(S.length != T.length) return false;

return isIsomorphic(S, T) && isIsomorphic(T, S);
}
}
``````