题解 | #最长回文子串#

#
# 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 A string字符串 
# @return int整型
#
class Solution:
    def check(self,n):
        if n==n[::-1]:
            return True
        else:
            return False
    
    def getLongestPalindrome(self , A: str) -> int:
        # write code here
        dp = [i for i in range(len(A))]
        for i in range(1,len(A)):
            this = A[i]
            lastleft = dp[i-1]
            if i-1-lastleft+1>1:
                if lastleft>0:
                    if this==A[lastleft-1]:
                        dp[i]=lastleft-1
                if dp[i]==i:
                    for k in range(lastleft,i,1):
                        if self.check(A[k:i+1]):
                            dp[i]=k
                            break
            else:
                if i-1>0:
                    if this==A[i-2]:
                        dp[i]=i-2
                if this==A[i-1]:
                    dp[i]=min(dp[i],i-1)
            dp[i] = min(dp[i],i)    

        maxc = 0
        for i in range(len(A)):
            now = i-dp[i]+1
            if now>maxc:
                maxc=now

        return maxc