290. Word Pattern

Easy

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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

Constraints:

• 1 <= pattern.length <= 300

• pattern contains only lower-case English letters.

• 1 <= s.length <= 3000

• s contains only lowercase English letters and spaces ' '.

• s does not contain any leading or trailing spaces.

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

class Solution:
    def wordPattern(self, pattern: str, s: str) -> bool:
        arr = s.split()
        vals = set()
        if len(pattern) != len(arr):
            return False
        d = {}
        for index in range(len(arr)):
            if pattern[index] in d:
                if d[pattern[index]] != arr[index]:
                    return False
            elif arr[index] in vals:
                return False
            else:
                vals.add(arr[index])
                d[pattern[index]] = arr[index]
        return True