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LeetCode/#regular-expression-matching
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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 = "c*a*b" | |
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 = "mis*is*p*." | |
Output: false | |
My code: | |
class Solution: | |
def isMatch(self, s, p): | |
""" | |
:type s: str | |
:type p: str | |
:rtype: bool | |
""" | |
i=0 | |
j=0 | |
self.dict={} | |
judge=self.check_match(s,p,i,j) | |
return bool(judge) | |
def check_match(self,s,p,i,j): | |
if (i,j) in self.dict.keys(): | |
return self.dict[i,j] | |
if j==len(p): | |
if i==len(s): | |
self.dict[i,j]=1 | |
else: | |
self.dict[i,j]=0 | |
else: | |
match=False | |
if i<len(s) and (p[j]==s[i] or p[j]=='.'): | |
match=True | |
if j+1<len(p) and p[j+1]=='*': | |
self.dict[i,j]=self.check_match(s,p,i,j+2) or match and self.check_match(s,p,i+1,j) | |
else: | |
self.dict[i,j]=match and self.check_match(s,p,i+1,j+1) | |
return self.dict[i,j] | |
Solution: | |
https://leetcode.com/problems/regular-expression-matching/ |