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 (.)".
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
Constraints:
- 0 <= s.length <= 20
- 0 <= 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.
class Solution {
public:
vector<string> letterCombinations(string digits) {
}
};🐛 Online Debuging: https://leetcode-cn.com/problems/regular-expression-matching
C++