在存在多个回文的情况下查找最长但字典序最小的回文

def find_longest_smallest_palindrome(s):
    length = len(s)
    start_index = 0
    max_length = 0
    
    # 从左到右找到第一个字符的索引
    for i in range(length):
        if s[i] < s[start_index]:
            start_index = i
    
    # 从第一个字符索引开始向两侧扩展
    left = start_index
    right = start_index
    
    while left >= 0 and right < length and s[left] == s[right]:
        left -= 1
        right += 1
    
    # 扩展范围的子串递归查找回文
    sub_string = s[left + 1: right]
    palindromes = find_longest_smallest_palindrome(sub_string) if len(sub_string) > 1 else [sub_string]
    
    # 将找到的回文按长度和字典序排序
    palindromes.sort(key=lambda x: (len(x), x))
    
    return palindromes[0]

# 示例输入
s = "abacdcab"
result = find_longest_smallest_palindrome(s)
print(result)