Convert BST to Greater Sum Tree

Given a Binary Search Tree (BST) of integers, your task is to convert it into a greater sum tree. In the greater sum tree, each node's value should be replaced with the sum of all nodes' values that are greater than the current node's value in the BST.

Example:

Input:

1
2 3
4 -1 5 6
-1 7 -1 -1 -1 -1
-1 -1

Output:

139 137 130 119 -1 104 75 -1 40 -1 -1 -1 -1 -1 -1

Explanation:

• 11 is replaced by the sum of {15 + 29 + 35 + 40} = 119
• 2 is replaced by the sum of {7 + 11 + 15 + 29 + 35 + 40} = 137
• 29 is replaced by the sum of {35 + 40} = 75
• 1 is replaced by the sum of {2 + 7 + 11 + 15 + 29 + 35 + 40} = 139
• 7 is replaced by the sum of {11 + 15 + 29 + 35 + 40} = 130
• 15 is replaced by the sum of {29 + 35 + 40} = 104
• 40 is replaced by 0 (since there are no greater values than 40)
• 35 is replaced by the sum of {40} = 40

Constraints:

• 1 <= T <= 100
• 0 <= N <= 1000
• 0 <= DATA <= 10 ^ 4 and DATA != -1

Note:

You must modify the existing tree without creating a new tree. The input tree nodes are provided in level-order format, using -1 to indicate null nodes.