LeetCode 010 Regular Expression Matching

题目描述：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

代码如下：

class Solution {

public:

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

        

        if(*p == '\0') return *s == '\0';

        

        //如果下一个字符不是*，那么就需要匹配当前的字符！

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

            

            //下一个字符相等，或者有一个是'.'，则匹配成功

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

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

            else 

                return false;

        }

        

        //下一个字符是*，则当前字符可以为0个或多个！

        else{

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

                if(isMatch(s, p + 2)) 

                    return true;

                s++;

            }

            return isMatch(s, p + 2);

        }

        

    }

};