LeetCode 2829. Determine the Minimum Sum of a k-avoiding Array

You are given two integers, n and k.

An array of distinct positive integers is called a k-avoiding array if there does not exist any pair of distinct elements that sum to k.

Return the minimum possible sum of a k-avoiding array of length n.

Example 1:

Input: n = 5, k = 4

Output: 18

Explanation: Consider the k-avoiding array [1,2,4,5,6], which has a sum of 18. It can be proven that there is no k-avoiding array with a sum less than 18.

Example 2:

Input: n = 2, k = 6

Output: 3

Explanation: We can construct the array [1,2], which has a sum of 3. It can be proven that there is no k-avoiding array with a sum less than 3.

Constraints:

• 1 <= n, k <= 50

数字都比较小，直接累加遍历即可，只是要保留一个集合，用于判断是否有差值在集合中即可；

下面是代码：

Runtime: 7 ms, faster than 100.00% of Java online submissions for Determine the Minimum Sum of a k-avoiding Array.

Memory Usage: 43.5 MB, less than 100.00% of Java online submissions for Determine the Minimum Sum of a k-avoiding Array.