题解 | #最长回文子串#

#参考：https://leetcode.cn/problems/longest-palindromic-substring/solution/dai-ma-sui-xiang-lu-5-zui-chang-hui-wen-kgyl1/
#DP
maxlen =0
left =0
right=0
text = input()
length = len(text)
dp=[[False]*length for _ in range(length)] #dp[i][j]表示text[i:j]是否是回文
for i in range(length):
    dp[i][i] = True
for i in range(length-1,-1,-1):
    for j in range(length):
        if text[i] == text[j]:
            if j-i < 3:
                dp[i][j]=True
            else:
                dp[i][j]=dp[i+1][j-1]
        if dp[i][j] and j-i+1>maxlen:
            left = i
            right = j
            maxlen=j-i+1
print(maxlen)