leetcode--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.

[java] view
plain copy

import java.util.Arrays;  

public class Solution {  

    public boolean isIsomorphic(String s, String t) {  

        if(s.length()!=t.length()) return false;  

        int[] map1 = new int[257];    

        int[] map2 = new int[257];        

        Arrays.fill(map1, -1);  

        Arrays.fill(map2, -1);  

        for(int i=0;i<s.length();i++){  

            if(map1[s.charAt(i)]==-1){  

                map1[s.charAt(i)] = t.charAt(i);  

            }else{  

                if(map1[s.charAt(i)] != t.charAt(i)){  

                    return false;  

                }  

            }  

            if(map2[t.charAt(i)]==-1){  

                map2[t.charAt(i)] = s.charAt(i);  

            }else{  

                if(map2[t.charAt(i)] != s.charAt(i)){  

                    return false;  

                }  

            }  

        }         

        return true;  

    }  

} 

原文链接http://blog.csdn.net/crazy__chen/article/details/45439841