LEETCODEEasy

Word Pattern

풀이일 2025 · 03 · 28기록 0 ms · 55.3 MB원문 leetcode ↗

Hash TableString

문제

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. Specifically:

Each letter in pattern maps to exactly one unique word in s.
Each unique word in s maps to exactly one letter in pattern.
No two letters map to the same word, and no two words map to the same letter.

Example 1:

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

Output: true

Explanation:

The bijection can be established as:

'a' maps to "dog".
'b' maps to "cat".

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.

풀이 TypeScript

function wordPattern(pattern: string, s: string): boolean {

  const words = s.split(' ');
  const chars = pattern.split('');
  const map = new Map<string, string>(); // char: word

  if(words.length !== chars.length) return false;
  if(new Set(words).size !== new Set(chars).size) return false;

  let index = 0;
  let length = pattern.length

  while(index < length) {
    const char = chars[index];
    const word = words[index];
    if (map.has(char)) {
      if (map.get(char) !== word) return false;
    } else {
      map.set(char, word);
    }
    index += 1
  }

  return true;
}

복사됨