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

Solution:

public class Solution {
    public boolean isMatch(String s, String p) {
        if(p.length()==0) return s.length()==0;
        if(p.length()==1 || p.charAt(1)!='*'){
            if(!s.isEmpty() && (s.charAt(0)==p.charAt(0) || p.charAt(0)=='.'))
                return isMatch(s.substring(1), p.substring(1));
            else 
                return false;
        }
        while(!s.isEmpty() && (s.charAt(0)==p.charAt(0) || p.charAt(0)=='.')){
            if(isMatch(s, p.substring(2))) return true;
            s = s.substring(1);
        }
        return isMatch(s, p.substring(2));
    }
}