【leetcode】【205】Isomorphic Strings

一、問題描述

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.

二、問題分析

顯然是一種map的關係，可以使用HashMap來處理，比較簡單。

三、Java AC代碼

public boolean isIsomorphic(String s, String t) {
        HashMap<Character, Character> map = new HashMap<Character, Character>();
		if (s.length()!=t.length()) {
			return false;
		}
		char chs;
		char cht;
		for(int i=0;i<s.length();i++){
			chs = s.charAt(i);
			cht = t.charAt(i);
			if (!map.containsKey(chs)) {
				if (map.values().contains(cht)) {
					return false;
				}
				map.put(chs, cht);
			}else {
				if (map.get(chs).equals(cht)) {
					continue;
				}else {
					return false;
				}
			}
		}
		return true;
    }