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
注意test:aa,a*;aaa,a*a;aaa,a*ac;
1 bool isMatch(char* s, char* p) { 2 if(*p==' ') return *s==' '; 3 if(*(p+1)=='*') 4 { 5 while(*s==*p||((*p=='.')&&(*s!=' '))) 6 { 7 if(isMatch(s,p+2)) return true; 8 s++; 9 } 10 return isMatch(s,p+2); //若为false,则当s不断++至‘ ’时，无法再次与p匹配，如aa，a*，当s==' '时，仍需与p+2匹配，输出正确结果 11 } 12 else 13 { 14 if(*s==*p||((*p=='.')&&(*s!=' '))) 15 return isMatch(s+1,p+1); 16 return false; 17 } 18 }