正则表达式匹配

 

class Solution {
public:
    bool matchTrue(char* str, char* pattern)
        {
        if(*str=='\0'&&*pattern=='\0')
          return true;
      else if(*str!='\0'&&*pattern=='\0')
          return false;
      if(*(pattern+1)=='*')
          {
          if(*str==*pattern||(*pattern=='.'&&*str!='\0'))
              return matchTrue(str,pattern+2)||matchTrue(str+1,pattern+2)||matchTrue(str+1,pattern);
          else return matchTrue(str,pattern+2);
      }
        else 
            {
            if(*str==*pattern||(*pattern=='.'&&*str!='\0'))
             return  matchTrue(str+1,pattern+1);
            else return false;
        }
        return false; 
    }
    bool match(char* str, char* pattern)
    {
        if(str==NULL||pattern==NULL)
            return false;
        return matchTrue(str,pattern);
    }
};