Regular Expression Matching

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

Solution:

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