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[LeetCode] Regular Expression Matching(递归)

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
class Solution {public:    bool isMatch(const char *s, const char *p) {        if (*p == \0) return *s == \0;  //empty        if (*(p + 1) != *) {//without *            if(!matchFirst(s,p))                return false;            return isMatch(s + 1, p + 1);        } else { //next: with a *            if(isMatch(s, p + 2))                 return true;    //try the length of 0            while ( matchFirst(s,p) )       //try all possible lengths                 if (isMatch(++s, p + 2))                    return true;        }    }private:    bool matchFirst(const char *s, const char *p){        return (*p == *s || (*p == . && *s != \0));    }};    

 

[LeetCode] Regular Expression Matching(递归)