题目:
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.
思路:终于又出个简单的了,读完题就能看到,用map保存映射,同时还要判断value是否被映射过,用set进行过滤
代码:
public class Solution { public boolean isIsomorphic(String s, String t) { Map<Character, Character> map = new HashMap<Character, Character>(); Set<Character> set = new HashSet<Character>(); StringBuilder sb = new StringBuilder(); for(int i = 0 ; i < len ; i++){ if(!map.containsKey(s.charAt(i))){ if(!set.contains(t.charAt(i))){ //过滤 value t map.put(s.charAt(i), t.charAt(i)); // s -> t set.add(t.charAt(i)); } else return false; } sb.append(map.get(s.charAt(i))); } return sb.toString().equals(t); } }