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.

• 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.

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