leetcode Regular Expression Matching

题目链接

public class Solution {
    public boolean isMatch(String s, String p) {

        return help(s,0,p,0);
    }

    public boolean help(String s,int startS,String p,int startP)   
    {
        if(startP>=p.length())
        {
            return startS>=s.length();
        }

        char pchar=p.charAt(startP);
        if(startP!=p.length()-1)
        {

            char pNextChar=p.charAt(startP+1);
            if(pNextChar=='*')
            {
                while(startS<s.length()&&(s.charAt(startS)==pchar||pchar=='.'))
                {
                    if(help(s, startS, p, startP+2))
                    {
                        return true;
                    }
                    startS++;
                }
                return help(s, startS, p, startP+2);
            }
            else
            {
                if(startS<s.length()&&(s.charAt(startS)==pchar||pchar=='.'))
                {
                    return help(s, startS+1, p, startP+1);
                }
                return false;
            }

        }
        else
        {
            if(startS<s.length()&&(s.charAt(startS)==pchar||pchar=='.'))
            {
                return help(s, startS+1, p, startP+1);
            }
            return false;
        }

    }
}

如果看不懂我的代码。下面我贴上一个牛人的代码

#include<iostream>
using namespace std;
bool isMatch(const char *s, const char *p) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (*p == 0) return *s == 0;
        if (*(p+1) != '*')
        {
            if (*s != 0 && (*p == *s || *p == '.')) return isMatch(s+1, p+1);

            return false;
        }
        else
        {
            // *s == *p
            while (*s != 0 && (*s == *p || *p == '.'))
            {
                if (isMatch(s, p+2)) return true;
                s++;
            }
            return (isMatch(s, p+2));
        }
    }

int main()
{
        if(isMatch("ab",".*c"))
        {

            cout<<"yes"<<endl;
        }
        else
        {

            cout<<"no"<<endl;
        }

}