306. Word Pattern
Easy
Bidirectional Mapping
Hashing
Problem
Given a pattern and a space-separated string s, determine whether s follows the same pattern. Each pattern character must map to exactly one word and each word must map to exactly one pattern character.
Examples
Example 1
Input: "abba", "dog cat cat dog"
Output: true
Example 2
Input: "abba", "dog cat cat fish"
Output: false
Example 3
Input: "aaaa", "dog cat cat dog"
Output: false
Constraints
� 1 <= pattern.length <= 300
� s contains lowercase English words separated by single spaces.
Hints
?? Split s into words first.
?? The number of words must equal pattern.length.
?? Use a bijection between pattern characters and words.
Expected Complexity
Time: O(n)
Space: O(n)
Follow-up
Can you implement the bijection using last-seen positions?
Practice Notes
Attempts: 0
Time spent: 0min
Hints used: 0
JavaScript
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Case 1
Case 2
Case 3
Input
"abba", "dog cat cat dog"Expected
true