题解 | 密码截取

string = input()
dp = [[False] * len(string) for _ in range(len(string))]
max_len = 0
for i in range(len(string)-1,-1,-1):
    for j in range(i,len(string)):
        if string[i] == string[j] and (j - i <= 1 or dp[i+1][j-1]):
            dp[i][j] = True
            max_len = max(max_len,j-i+1)
print(max_len)

通过动态规划判断回文字串数量的方法，每次都存最大长度