Python | Leetcode Python题解之第10题正则表达式匹配-题解：

class Solution:
    def isMatch(self, s: str, p: str) -> bool:

        m, n = len(s), len(p)
        dp = [False] * (n+1)
        
        # 初始化
        dp[0] = True
        for j in range(1, n+1):
            if p[j-1] == '*':
                dp[j] = dp[j-2]

        # 状态更新
        for i in range(1, m+1):
            dp2 = [False] * (n+1)           # 滚动数组
            for j in range(1, n+1):
                if s[i-1] == p[j-1] or p[j-1] == '.':
                    dp2[j] = dp[j-1]
                elif p[j-1] == '*':
                    if s[i-1] != p[j-2] and p[j-2] != '.':
                        dp2[j] = dp2[j-2]
                    else:
                        dp2[j] = dp2[j-2] | dp[j]
            dp = dp2                        # 滚动数组

            if sum(dp) == 0:                # 提前结束
                return False
        
        return dp[n]