Word Pattern

word_pattern.py

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


class Solution:
    def wordPattern(self, pattern: str, str: str) -> bool:
        words = str.split(" ")
        if len(pattern) != len(words):
            return False
        map_chars = {}
        map_words = {}
        for c, word in zip(pattern, words):
            if c in map_chars:
                if map_chars[c] != word:
                    return False
            else:
                if word in map_words:
                    return False
                else:
                    map_chars[c] = word
                    map_words[word] = c
        return True