[LeetCode] Word Pattern 词语模式

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

Examples:

1. pattern = "abba", str = "dog cat cat dog" should return true.
2. pattern = "abba", str = "dog cat cat fish" should return false.
3. pattern = "aaaa", str = "dog cat cat dog" should return false.
4. pattern = "abba", str = "dog dog dog dog" should return false.

Notes:

1. Both pattern and str contains only lowercase alphabetical letters.
2. Both pattern and str do not have leading or trailing spaces.
3. Each word in str is separated by a single space.
4. Each letter in pattern must map to a word with length that is at least 1.

Credits:
Special thanks to @minglotus6 for adding this problem and creating all test cases.

[LeetCode] Word Pattern 词语模式

原文：http://www.cnblogs.com/grandyang/p/4857022.html