题目链接：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.
// 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;
}
}