459. Repeated Substring Pattern

Level - easy

Task

Given a string s, check if it can be constructed by taking a substring of it and appending multiple copies of the substring together.

Методы решения

1. Brute force O(n^2)
2. Конкатенация и подстрока O(n)
3. Алгоритм Кнута-Морриса-Пратта(KMP) O(n)
4. Использовать хэшь-функцию O(n)
5. Конечный автомат O(n)
6. Регулярные выражения O(n)

Example 1:

Input: s = "abab"
Output: true
Explanation: It is the substring "ab" twice.

Example 2:

Input: s = "aba"
Output: false

Example 3:

Input: s = "abcabcabcabc"
Output: true
Explanation: It is the substring "abc" four times or the substring "abcabc" twice.

Constraints:

• 1 <= s.length <= 104
• s consists of lowercase English letters.