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44. Wildcard Matching

String Dynamic Programming Greedy Recursion

Problem - Wildcard Matching

Hard

Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '*' where:

  • '?' Matches any single character.
  • '*' Matches any sequence of characters (including the empty sequence).

The matching should cover the entire input string (not partial).

 

Example 1:

Input: s = "aa", p = "a"
Output: false
Explanation: "a" does not match the entire string "aa".

Example 2:

Input: s = "aa", p = "*"
Output: true
Explanation: '*' matches any sequence.

Example 3:

Input: s = "cb", p = "?a"
Output: false
Explanation: '?' matches 'c', but the second letter is 'a', which does not match 'b'.

 

Constraints:

  • 0 <= s.length, p.length <= 2000
  • s contains only lowercase English letters.
  • p contains only lowercase English letters, '?' or '*'.

Solutions

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class Solution:
    def isMatch(self, s: str, p: str) -> bool:
        @cache
        def dfs(i: int, j: int):
            if i >= len(s):
                return j >= len(p) or (p[j] == "*" and dfs(i, j + 1))
            if j >= len(p):
                return False
            if p[j] == "*":
                return dfs(i, j+1) or dfs(i+1, j)
            return (p[j] == "?" or s[i] == p[j]) and dfs(i + 1, j + 1)

        return dfs(0, 0)

Submission Stats:

  • Runtime: 377 ms (60.37%)
  • Memory: 128.3 MB (11.67%)