[leetcode] 459. Repeated Substring Pattern @ python

原题

Given a non-empty string check if it can be constructed by taking a substring of it and appending multiple copies of the substring together. You may assume the given string consists of lowercase English letters only and its length will not exceed 10000.

Example 1:

Input: “abab”
Output: True
Explanation: It’s the substring “ab” twice.
Example 2:

Input: “aba”
Output: False
Example 3:

Input: “abcabcabcabc”
Output: True
Explanation: It’s the substring “abc” four times. (And the substring “abcabc” twice.)

解法

从可能的子字符串的长度推算, 子字符串最短长度为1, 最长长度为len(s)//2, 遍历可能的长度, 如果能被len(s) 整除, 检查重复子字符串能否构成s.

代码

class Solution(object):
    def repeatedSubstringPattern(self, s):
        """
        :type s: str
        :rtype: bool
        """
        l = len(s)
        for length in range(1, l//2+1):
            if l % length == 0:
                sub = s[:length]
                repeat = l//length
                if sub * repeat == s:
                    return True
        
        return False