题目链接:https://leetcode.com/problems/isomorphic-strings/
题目:
s and t, determine if they are isomorphic.
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."foo"
, "bar"
, return false."paper"
, "title"
, return true.
Note:
You may assume both s and t
思路:
用HashMap存储字符之间映射关系,要注意是双向映射即a映射到b,b也要映射到a,用hashmap要判断两次。
算法:
1. public boolean isIsomorphic(String s, String t) {
2. char strs[] = s.toCharArray();
3. char patterns[] = t.toCharArray();
4. new HashMap<Character, Character>();
5.
6. for (int i = 0; i < strs.length; i++) {
7. if (maps.containsKey(strs[i])) {
8. if (!(maps.get(strs[i]).charValue() == patterns[i])) {
9. return false;
10. }
11. else {
12. maps.put(strs[i], patterns[i]);
13. }
14. }
15.
16. maps.clear();
17. for (int i = 0; i < patterns.length; i++) {
18. if (maps.containsKey(patterns[i])) {
19. if (!(maps.get(patterns[i]).charValue() == strs[i])) {
20. return false;
21. }
22. else {
23. maps.put(patterns[i], strs[i]);
24. }
25. }
26. return true;
27. }
1.