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.

Example 1:

Input: pattern = "abba", str = "dog cat cat dog"
Output: true

Example 2:

Input:pattern = "abba", str = "dog cat cat fish"
Output: false

Example 3:

Input: pattern = "aaaa", str = "dog cat cat dog"
Output: false

Example 4:

Input: pattern = "abba", str = "dog dog dog dog"
Output: false


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


class Solution(object):
    def wordPattern(self, pattern, str):
        :type pattern: str
        :type str: str
        :rtype: bool
        str = str.strip().split(' ')
        if len(str) != len(pattern):
            return False

        pattern_dict = dict()
        seen_words = set()

        for i, c in enumerate(pattern):
            if c in pattern_dict:
                if str[i] != pattern_dict[c]:
                    return False
                if str[i] not in seen_words:
                    pattern_dict[c] = str[i]
                    return False

        return True