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 *.
Example 1:
Input:
s = "aa"
p = "a"
Output: false
Explanation: "a" does not match the entire string "aa".
Example 2:
Input:
s = "aa"
p = "a"
Output: true
Explanation: '' means zero or more of the precedeng element, 'a'. Therefore, by repeating 'a' once, it becomes "aa".
Example 3:
Input:
s = "ab"
p = "."
Output: true
Explanation: "." means "zero or more (*) of any character (.)".
Example 4:
Input:
s = "aab"
p = "cab"
Output: true
Explanation: c can be repeated 0 times, a can be repeated 1 time. Therefore it matches "aab".
Example 5:
Input:
s = "mississippi"
p = "misisp*."
Output: false
Solution1:
import re
class Solution:
def isMatch(self, s, p):
"""
:type s: str
:type p: str
:rtype: bool
"""
return re.match(p + '$',s)!=None
Solution2:
import re
class Solution:
def isMatch(self, s, p):
"""
:type s: str
:type p: str
:rtype: bool
"""
return re.search('^' + p + '$',s)!=None
'^'表示匹配字符串开头,'$'表示匹配字符串结尾。
re.match只匹配字符串的开始,如果字符串开始不符合正则表达式,则匹配失败,函数返回None;而re.search匹配整个字符串,直到找到一个匹配。