题目描述：
Given a pattern and a string str, find if str follows the same pattern.
Examples:
pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish ...
Given a pattern and a string str, find if str follows the same pattern.
Examples:
pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish ...