// 29 / 29 test cases passed. // Status: Accepted // Runtime: 390 ms // Submitted: 1 minute ago public class Solution { public boolean isIsomorphic(String s, String t) { Map<Character, Character> sm = new HashMap<Character, Character>(); Map<Character, Character> tm = new HashMap<Character, Character>(); for (int i = 0; i < s.length(); i++) { char char_s = s.charAt(i); char char_t = t.charAt(i); if(sm.get(char_s) == null) { if(tm.get(char_t) == null) { sm.put(char_s, char_t); tm.put(char_t, char_s); } else return false; } else { if(tm.get(char_t) == null) return false; if(!(sm.get(char_s) == char_t && tm.get(char_t) == char_s)) return false; } } return true; } }