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

<pre name="code" class="cpp"> bool isMatch(const char *s, const char *p) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
if (*p == '\0') return *s == '\0';
if (*(p+1) == '*') // 模式串的下一个字符是'*'
{
while(*p == *s || (*p == '.' && *s != '\0'))
{
//字符串与模式串匹配0/1/2...个字符的情况
if (isMatch(s++, p+2))
return true;
}
// 字符串与模式串不能匹配
return isMatch(s, p+2);
}
else
{
if (*p == *s || (*p == '.' && *s != '\0'))
return isMatch(s+1, p+1);
return false;
}
}