public class Solution
extends Object
2310 - Sum of Numbers With Units Digit K\.
Medium
Given two integers `num` and `k`, consider a set of positive integers with the following properties:
* The units digit of each integer is `k`.
* The sum of the integers is `num`.
Return _the **minimum** possible size of such a set, or_ `-1` _if no such set exists._
Note:
* The set can contain multiple instances of the same integer, and the sum of an empty set is considered `0`.
* The **units digit** of a number is the rightmost digit of the number.
**Example 1:**
**Input:** num = 58, k = 9
**Output:** 2
**Explanation:**
One valid set is [9,49], as the sum is 58 and each integer has a units digit of 9.
Another valid set is [19,39].
It can be shown that 2 is the minimum possible size of a valid set.
**Example 2:**
**Input:** num = 37, k = 2
**Output:** -1
**Explanation:** It is not possible to obtain a sum of 37 using only integers that have a units digit of 2.
**Example 3:**
**Input:** num = 0, k = 7
**Output:** 0
**Explanation:** The sum of an empty set is considered 0.
**Constraints:**
* `0 <= num <= 3000`
* `0 <= k <= 9`