p290

发表于 | 分类于 |

LeetCode p290 Word Pattern 题解

1.题目：

Given a pattern and a string str, find if str follows the same pattern.

Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.

Examples:

pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish" should return false.
pattern = "aaaa", str = "dog cat cat dog" should return false.
pattern = "abba", str = "dog dog dog dog" should return false.

Notes:
You may assume pattern contains only lowercase letters, and str contains lowercase letters separated by a single space.

题意：

判断字符串格式是否与图章一致。

2.解题思路:

使用hashmap和hashset

3.代码

[title] [] [url] [link text]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
 
public class Solution {
    public boolean wordPattern(String pattern, String str) {
        String[] list = str.split(" ");
		if (pattern.length() != list.length)
			return false;
		HashMap<Character, String> hashMap = new HashMap<Character, String>();
		HashSet<String> set = new HashSet<String>();
		for (int i = 0; i < pattern.length(); i++) {
			String aString = hashMap.get(pattern.charAt(i));
			if (aString == null) {
				if (set.contains(list[i]))
					return false;
				hashMap.put(pattern.charAt(i), list[i]);
				set.add(list[i]);
			} else {
				if (!list[i].equals(aString))
					return false;
			}
		}
		return true;
    }
}

4.一些总结：