root of a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus the sum of all keys greater than the original key in BST.
As a reminder, a binary search tree is a tree that satisfies these constraints:
- The left subtree of a node contains only nodes with keys less than the node's key.
- The right subtree of a node contains only nodes with keys greater than the node's key.
- Both the left and right subtrees must also be binary search trees.
4 (30) / \ / \ 1 (36) 6 (21) / \ / \ / \ / \ 0 (36) 2 (35) 5 (26) 7 (15) \ \ 3 (33) 8 (8) Input: root = [4,1,6,0,2,5,7,null,null,null,3,null,null,null,8] Output: [30,36,21,36,35,26,15,null,null,null,33,null,null,null,8]
Input: root = [0,null,1] Output: [1,null,1]
- The number of nodes in the tree is in the range
-104 <= Node.val <= 104
- All the values in the tree are unique.
rootis guaranteed to be a valid binary search tree.