Wildcard Matching — LeetCode 44 Python Solution

The problem

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).

Example

Input

s = "aa", p = "a"

Output

false

Explanation

"a" does not match the entire string "aa".

Python solution

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

        return dfs(0, 0)

Complexity

Pattern: Greedy

Take the locally best option every time — when you can prove that never costs you later. LeetCode 44. Wildcard Matching is filed here because LeetCode tags it Greedy, which is the vocabulary this hub collects.

The greedy guide has the Python template for the pattern and the 346 LeetCode problems that use it.

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