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.
题目分析，两个字符串之间的一一映射关系，采用hash来处理，因为由两个字符串构成，因此必须构建两个hash映射表，保证两个字符串中字符之间的一一对应关系
public class Solution {
public boolean isIsomorphic(String s, String t) {
HashMap<Character,Character> map1=new HashMap<Character, Character>();
HashMap<Character,Character> map2=new HashMap<Character, Character>();
for(int i=0;i<s.length();i++)
{
if(map1.get(s.charAt(i))==null)
map1.put(s.charAt(i),t.charAt(i));
if(map2.get(t.charAt(i))==null)
map2.put(t.charAt(i),s.charAt(i));
if(map1.get(s.charAt(i))!=t.charAt(i)||map2.get(t.charAt(i))!=s.charAt(i))
return false;
}
return true;
}
}
Leetcode#205Isomorphic Strings
原文：http://7061299.blog.51cto.com/7051299/1640264