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

class Solution {public:    bool isMatch(const char *s, const char *p) {        if(*p == NULL){            return *s == NULL;        }        if(*(p+1) != '*'){            if(*s != NULL && (*s == *p || *p == '.')){                return isMatch(++s,++p);            }            else                return false;        }        else{            while(*s != NULL && (*p == *s || *p == '.')){                if(isMatch(s,p+2)){                    return true;                }                s++;            }            return isMatch(s, p+2);        }    }};