205. Isomorphic Strings

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.

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.

Analysis:

Identical problem to word pattern. 

Solution:

class Solution {
    public boolean isIsomorphic(String s, String t) {
        Map<Character, Character> map = new HashMap<>();
        for (int i = 0; i < strs.length; i++) {
            char c1 = s.charAt(i);
            char c2 = t.charAt(i);
            String word = strs[i];
            if (map.containsKey(c1) && !map.get(c1).equals(c2))
                return false;
            if (!map.containsKey(c1) && map.containsValue(c2)) 
                return false;
            map.put(c1, c2);
        }
        return true;
    }
}