10. Regular Expression Matching

Hard

String,Dynamic Programming,Recursion

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Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*' where:

• '.' Matches any single character.​​​​
• '*' Matches zero or more of the preceding element.

The matching should cover the entire input string (not partial).

 

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 preceding 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 (.)".

 

Constraints:

• 1 <= s.length <= 20
• 1 <= p.length <= 30
• s contains only lowercase English letters.
• p contains only lowercase English letters, '.', and '*'.
• It is guaranteed for each appearance of the character '*', there will be a previous valid character to match.

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Submissions

Time Submitted	Status	Runtime	Memory	Language
06/21/2022 21:58	Accepted	3 ms	42.4 MB	java
09/24/2021 16:47	Accepted	2 ms	37.7 MB	java
09/24/2021 16:46	Wrong Answer	N/A	N/A	cpp
09/24/2021 16:43	Accepted	164 ms	13.4 MB	cpp