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.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;
}
}