正则匹配

lc10, *可以匹配0个或者多个前一个字符

class Solution(object):
    def isMatch(self, s, p):
        """
        :type s: str
        :type p: str
        :rtype: bool
        """
        m=len(s)+1
        n=len(p)+1

        dp=[[False for j in range(n)] for i in range(m)] 
        dp[0][0]=True

        for j in range(1,n):
            if(j>=2 and p[j-1]=="*" and dp[0][j-2]==True ):
                dp[0][j]=True

        for i in range(1,m):
            for j in range(1,n):
                if(s[i-1]==p[j-1] or p[j-1]=="."):
                    dp[i][j]=dp[i-1][j-1]
                elif p[j-1]=="*":
                    if(s[i-1]!=p[j-2] and p[j-2]!="."):
                        dp[i][j]=dp[i][j-2]
                    else:
                        dp[i][j]=dp[i][j-2] or dp[i][j-1] or dp[i-1][j]
        
        return dp[-1][-1]

lc44 *可以匹配任意字符串

class Solution(object):
    def isMatch(self, s, p):
        """
        :type s: str
        :type p: str
        :rtype: bool
        """
        m=len(s)+1
        n=len(p)+1

        dp=[[False for j in range(n)] for i in range(m)]
        dp[0][0]=True

        for j in range(1,n):
            if (p[j-1]=='*' and dp[0][j-1]==True):
                dp[0][j]=True
        
        for i in range(1,m):
            for j in range(1,n):
                if(s[i-1]==p[j-1] or p[j-1]=='?'):
                    dp[i][j]=dp[i-1][j-1]
                elif p[j-1]=="*":
                            # *表示空字符时； *表示任意字符，
                    dp[i][j]=dp[i][j-1] or dp[i-1][j]

        return dp[-1][-1]