[question brushing diary] longest palindrome substring

Sum up the questions ：
The title is ：https://leetcode.cn/problems/longest-palindromic-substring/

MANCHE thought ： Insert # As isolation .
First , See the title , I think we can use the central diffusion method . However, we need to discuss whether odd numbers or even numbers . for example aa and aba It's a little troublesome . If you deal with it , Insert #, Then the palindrome number traversing any character can be calculated as an odd number . Because the original same characters are separated .

        #manche  Algorithm 
        s_ = "#"+"#".join(s)+ "#"
        ans = 0
        for index,value in enumerate(s_):
            #  Odd number ：
            left,right,n = index,index,len(s_)
            while True:
                left -= 1
                right += 1
                if left>=0 and right < n:# The boundary conditions . Be similar to Ｃ++ Medium ++left perhaps ++right.
                    pass
                else:
                    left += 1#  Add back if you reduce more . Step back .
                    right -= 1
                    break
                if s_[left]==s_[right]:#  If the left and right strings are the same , Continue to cycle .
                    pass
                else:
                    left += 1#  Traverse to unequal boundaries , Step back and jump out of the loop .
                    right -= 1
                    break
            # print("ans\t",s_[left:right+1])
            if ans < (len(s_[left:right+1])-1)//2:
                res = s_[left:right+1]
                ans = (len(s_[left:right+1])-1)//2
            
        return ''.join(res.split('#'))