题解 | #正则表达式匹配#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param str string字符串 
     * @param pattern string字符串 
     * @return bool布尔型
     */
    bool match(string str, string pattern) {
        // write code here
        if(pattern.empty())
            return str.empty();
        
        bool firstMatch = (!str.empty() && (str[0]==pattern[0] || pattern[0]=='.'));

        if(pattern.length()>=2&&pattern[1]=='*')
        {
            return (match(str, pattern.substr(2)) || (firstMatch && match(str.substr(1), pattern)));
        }else {
            return firstMatch && match(str.substr(1),  pattern.substr(1));
        }
    }
};