2310-sum-of-numbers-with-units-digit-k.adoc

2310. Sum of Numbers With Units Digit K

{leetcode}/problems/sum-of-numbers-with-units-digit-k/[LeetCode - 2310. Sum of Numbers With Units Digit K ^]

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

思路分析

一刷

link:{sourcedir}/_2310_SumOfNumbersWithUnitsDigitK.java[role=include]

参考资料