Given an integer array nums of length n and an integer k, return the kth smallest subarray sum.
A subarray is defined as a non-empty contiguous sequence of elements in an array. A subarray sum is the sum of all elements in the subarray.
Example 1:
Input: nums = [2,1,3], k = 4 Output: 3 Explanation: The subarrays of [2,1,3] are: - [2] with sum 2 - [1] with sum 1 - [3] with sum 3 - [2,1] with sum 3 - [1,3] with sum 4 - [2,1,3] with sum 6 Ordering the sums from smallest to largest gives 1, 2, 3, 3, 4, 6. The 4th smallest is 3.
Example 2:
Input: nums = [3,3,5,5], k = 7 Output: 10 Explanation: The subarrays of [3,3,5,5] are: - [3] with sum 3 - [3] with sum 3 - [5] with sum 5 - [5] with sum 5 - [3,3] with sum 6 - [3,5] with sum 8 - [5,5] with sum 10 - [3,3,5], with sum 11 - [3,5,5] with sum 13 - [3,3,5,5] with sum 16 Ordering the sums from smallest to largest gives 3, 3, 5, 5, 6, 8, 10, 11, 13, 16. The 7th smallest is 10.
Constraints:
n == nums.length1 <= n <= 2 * 1041 <= nums[i] <= 5 * 1041 <= k <= n * (n + 1) / 2