205. 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.

you can use two maps to map the chars from each string,however, you can use the index information saved inside two strings, if two chars are 'equal', they should have same index.

public class Solution {
    public boolean isIsomorphic(String s, String t) {
        if(s.length() != t.length()) return false;
        int[] m1 = new int[256];
        int[] m2 = new int[256];
        for(int i=0; i< s.length(); i++){
            if(m1[s.charAt(i)] != m2[t.charAt(i)]) return false;

            m1[s.charAt(i)] = i+1;
            m2[t.charAt(i)] = i+1;
        }

        return true;
    }
}