leetcode[10]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") → false

isMatch("aa","aa") → true

isMatch("aaa","aa") → false

isMatch("aa", "a*") → true

isMatch("aa", ".*") → true

isMatch("ab", ".*") → true

isMatch("aab", "c*a*b") → true

class Solution {

public:

    bool isMatch(const char *s, const char *p) {

    if (*p=='\0')

        return *s=='\0';

    if (*(p+1)=='*')

    {

        while((*s!='\0')&&((*s==*p)||(*p=='.')))

        {

            if (isMatch(s,p+2))

            {

                return true;

            }

            else

            {

                s++;

            }

        }

        return isMatch(s,p+2);

    } 

    else 

    {

        if((*s!='\0')&&((*s==*p)||(*p=='.')))

        {

            return isMatch(s+1,p+1);

        }

        return false;

    }

    }

};