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.
问题：给定两个字符串，判断他们是否同构。
当字符串 s 中的字符可以被替换得到另一个字符串 t , 则表示字符串 s 和 t 是同构。
import static java.lang.System.out; import java.util.Hashtable; public class Solution { public boolean isIsomorphic(String s, String t) {
Hashtable<Character, Character> s_t = new Hashtable<Character, Character>(); Hashtable<Character, Character> t_s = new Hashtable<Character, Character>(); int length = s.length(); for(int i = 0; i < length; i++){
Character ss = s.charAt(i); Character tt = t.charAt(i); if(s_t.containsKey(ss) || t_s.containsKey(tt)){ if(s_t.get(ss) == tt && t_s.get(tt) == ss){ continue; }else{ return false; } }else{ s_t.put(ss, tt); t_s.put(tt, ss); } } return true; } }
[LeetCode] 205. Isomorphic Strings 解题思路 - Java
原文：http://www.cnblogs.com/TonyYPZhang/p/5476191.html