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

 1 class Solution { 2 public: 3     bool isMatch(const char *s, const char *p) { 4         5         if(s==NULL||p==NULL) return false; 6         if(*p==‘\0‘&&*s==‘\0‘) return true; 7         if(*p==‘\0‘&&*s!=‘\0‘) return false; 8       9         //如果模式串下一个字符为*    10         if(*(p+1)==‘*‘)11         {12             //循环比较当前字符与模式串字符是否相等13             while((*s!=‘\0‘&&*p==‘.‘)||(*s==*p))14             {15                 //防止这种情况出现："aaa", "a*a"16                 if(isMatch(s,p+2)) return true;17                 s++;18             }19             return isMatch(s,p+2);20         }21         else if((*s!=‘\0‘&&*p==‘.‘)||*s==*p)22         {23             //如果当前元素相等，则开始匹配下一个元素24             return isMatch(s+1,p+1);25         }26         return false;27     }28 };