The?k-beauty?of an integer?num?is defined as the number of?substrings?of?num?when it is read as a string that meet the following conditions:

• It has a length of?k.

• It is a divisor of?num.

Given integers?num?and?k, return?the k-beauty of?num.

Note:

• Leading zeros?are allowed.

• 0?is not a divisor of any value.

A?substring?is a contiguous sequence of characters in a string.

?

Example 1:

Input: num = 240, k = 2Output: 2Explanation: The following are the substrings of num of length k: - "24" from "240": 24 is a divisor of 240. - "40" from "240": 40 is a divisor of 240. Therefore, the k-beauty is 2.

Example 2:

Input: num = 430043, k = 2Output: 2Explanation: The following are the substrings of num of length k: - "43" from "430043": 43 is a divisor of 430043. - "30" from "430043": 30 is not a divisor of 430043. - "00" from "430043": 0 is not a divisor of 430043. - "04" from "430043": 4 is not a divisor of 430043. - "43" from "430043": 43 is a divisor of 430043. Therefore, the k-beauty is 2.

難得的100%啊。。。

Runtime:?0 ms, faster than?100.00%?of?Java?online submissions for?Find the K-Beauty of a Number.

Memory Usage:?39.2 MB, less than?63.48%?of?Java?online submissions for?Find the K-Beauty of a Number.