标签：
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
比较与Wildcard Matching的关系。
在Wildcard Matching中的‘?‘与此题的‘.‘一致。
但是Wildcard Matching中‘*‘本身代表通配符，而此题‘*‘代表前一个字符重复0或若干次。
class Solution { public: bool isMatch(const char *s, const char *p) { if(*p == 0) { if(*s == 0) return true; else return false; } //to here, p is not NULL if(*(p+1) == ‘*‘) { //case 1: *p matches 0 chars in s if(isMatch(s, p+2)) return true; //case 2: try all the possible number of chars that *p matches in s while(matchFirst(s, p)) { s ++; if(isMatch(s, p+2)) return true; } } else { if(matchFirst(s, p)) return isMatch(s+1, p+1); else return false; } } bool matchFirst(const char *s, const char *p) {//match the first char if((*p==*s) || (*p==‘.‘ && *s != 0)) return true; else return false; } };
【LeetCode】Regular Expression Matching
标签：
原文地址：http://www.cnblogs.com/ganganloveu/p/4176627.html
