[LeetCode] 686. Repeated String Match

轉自LeetCode

Given two strings A and B, find the minimum number of times A has to be repeated such that B is a substring of it. If no such solution, return -1.

For example, with A = "abcd" and B = "cdabcdab".

Return 3, because by repeating A three times (“abcdabcdabcd”), B is a substring of it; and B is not a substring of A repeated two times ("abcdabcd").

Note:
The length of A and B will be between 1 and 10000.

<Solution>

想法如下

• 如果 B 要是 A 的 substring，那麼 A 的長度一定要大於等於 B

• 所以先重複Ａ，直到長度至少等於 B，檢查 B 是不是子字串

• 如果不是，再重複一次 A(當前一次的長度等於B時，還沒辦法包含所有情況)，然後檢查 B 是不是子字串

• 如果都不是，就回傳 -1

code 如下

Java(參考解答)

Kotlin