【LeetCode】 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.

public class Solution {    public boolean isIsomorphic(String s, String t) {        HashMap<Character, Character> hs = new HashMap<Character, Character>();        for (int i = 0; i < s.length(); i++) {            char cs = s.charAt(i);            char ct = t.charAt(i);            Character temp = hs.get(cs);            if (temp == null) {                hs.put(cs, ct);            } else if (!temp.equals(ct)) {                return false;            }        }        hs.clear();        for (int i = 0; i < t.length(); i++) {            char cs = s.charAt(i);            char ct = t.charAt(i);            Character temp = hs.get(ct);            if (temp == null) {                hs.put(ct, cs);            } else if (!temp.equals(cs)){                return false;            }        }        return true;    }}