【Leetcode/python】10. Regular Expression Matching

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).

Note:

s could be empty and contains only lowercase letters a-z.
p could be empty and contains only lowercase letters a-z, and characters like . or *.

Python 中直接用re模块，大杀器，关于.和*的用法，此处于re模块中相同。

re模块

• re.match(p, s): 找出匹配的字符串

match对象

• .start(): 匹配的起始位置
• .end(): 匹配的终点位置
• .span(): 返回( .start(), .end())
• .group(): 匹配的字符串

class Solution:
    def isMatch(self, s, p):
        """
        :type s: str
        :type p: str
        :rtype: bool
        """
        res = re.match(p, s)
        # need this if, if not, u will get an error: 'NoneType' object has no attribute 'group'
        if res == None:
            return False
        else:
            return res.group() == s