[LeetCode 205] Isomorphic Strings

题目链接：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.

// 29 / 29 test cases passed.
// Status: Accepted
// Runtime: 390 ms
// Submitted: 1 minute ago


public class Solution {
    public boolean isIsomorphic(String s, String t) {
        Map<Character, Character> sm = new HashMap<Character, Character>();
        Map<Character, Character> tm = new HashMap<Character, Character>();
        for (int i = 0; i < s.length(); i++) {
			char char_s = s.charAt(i);
			char char_t = t.charAt(i);
			if(sm.get(char_s) == null) {
				if(tm.get(char_t) == null) {
					sm.put(char_s, char_t);
					tm.put(char_t, char_s);
				} else	return false;
			} else {
				if(tm.get(char_t) == null) return false;
				if(!(sm.get(char_s) == char_t && tm.get(char_t) == char_s))
					return false;
			}
		}
        return true;
    }
}

[LeetCode 205] Isomorphic Strings

原文：http://blog.csdn.net/ever223/article/details/45366829