#10

Regular Expression Matching

hard· 2-D DPruns: 0

Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*'. '.' matches any single character; '*' matches zero or more of the preceding element. The matching should cover the entire input string, not partial.

wpm 0acc 100%time 0:000 / 688

class Solution:
    def isMatch(self, s: str, p: str) -> bool:
        m, n = len(s), len(p)
        dp = [[False] * (n + 1) for _ in range(m + 1)]
        dp[0][0] = True
        for j in range(2, n + 1):
            if p[j - 1] == "*":
                dp[0][j] = dp[0][j - 2]
        for i in range(1, m + 1):
            for j in range(1, n + 1):
                if p[j - 1] == "*":
                    dp[i][j] = dp[i][j - 2]
                    if p[j - 2] == "." or p[j - 2] == s[i - 1]:
                        dp[i][j] = dp[i][j] or dp[i - 1][j]
                elif p[j - 1] == "." or p[j - 1] == s[i - 1]:
                    dp[i][j] = dp[i - 1][j - 1]
        return dp[m][n]

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