Maximum Sum Subarray Sum upto k

Given an array nums and a target value k, find the maximum sum of a subarray that sums less than or equal to k. If there isn't one, return 0 instead.
Note:
The sum of the entire nums array is guaranteed to fit within the 32-bit signed integer range.
Example 1:
Input: nums = [1, -1, 5, -2, 3], k = 4
Output: 4 
Explanation: The subarray [1, -1, 5, -2] sums to 3 and is closest <= k.
Example 2:
Input: nums = [3, -1, 2, 7], k = 5
Output: 4 
Explanation: The subarray [3, -1, 2] sums to 4 and is closest <= 5.
Follow Up:
Can you do it in O(n) time?
----
Intuition
Sub array sum => preprocess input to get range sum in const time => create prefix sum
Sum from i to j = prefix[j] - prefix[i - 1],  length of subarray = j - 1

Problem reduces to Max (prefix[j] - prefix[i - 1]) such that prefix[j] - prefix[i] <= k

Instead of brute force, we can lookup complement prefix[index] - k from Tree Set

If such complement exists, check if its potentially greater than previous answer
---
Time - O(N Log N)
Space - O(N)
---
Related problems
325-maximum-size-subarray-sum-equals-k
---