Word Pattern

Word Pattern

Given a pattern and a string s, find if s 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 s.

Example 1:

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

Example 2:

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

Example 3:

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

Example 4:

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

Constraints:

• 1 <= pattern.length <= 300

• pattern contains only lower-case English letters.

• 1 <= s.length <= 3000

• s contains only lower-case English letters and spaces ' '.

• s does not contain any leading or trailing spaces.

• All the words in s are separated by a single space.

Solutions

🐍 Python

class Solution:
    def wordPattern(self, pattern: str, words: str) -> bool:
        d = dict()
        if len(pattern) != len(words.split()):
            return False

        for a, b in zip(pattern, words.split()):
            if a in d.keys():
                if d[a] != b:
                    return False
            elif b not in d.values():
                d[a] = b
            else:
                return False

        return True