leetcode:Regular Expression Matching [10]

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).The function prototype should be:bool isMatch(const char *s, const char *p)Some examples:isMatch("aa","a") → falseisMatch("aa","aa") → trueisMatch("aaa","aa") → falseisMatch("aa", "a*") → trueisMatch("aa", ".*") → trueisMatch("ab", ".*") → trueisMatch("aab", "c*a*b") → true

class Solution {public:bool isMatch(string s, string p) {if (p.length() == 0) return s.length() == 0;if (p[1] == '*') {while (p[0] == s[0] || (p[0] == '.'&&s.length() != 0)) {if (isMatch(s, p.substr(2)))return true;s = s.substr(1);}}else {if (p[0] == s[0] || (p[0] == '.'&&s.length() != 0)) return isMatch(s.substr(1), p.substr(1));return false;}return false;}};