dsa · easy
Tree Tilt
The **tilt** of a binary-tree node is the absolute difference between the sum of every value in its left subtree and the sum of every value in its right subtree. An empty subtree sums to 0. The tilt of the whole tree is the sum of every node's tilt.
Arguments
root— binary tree as nested [val, left, right] or None
Each node is [val, left, right] or None. Return the tree tilt. An empty tree has tilt 0.
Example
root = [1,[2,None,None],[3,None,None]]
- Node 2:
|0 - 0| = 0 - Node 3:
|0 - 0| = 0 - Node 1:
|2 - 3| = 1
Total tilt 1.
[4,[2,[3,None,None],[5,None,None]],[9,None,[7,None,None]]] has node tilts 0, 0, 0, 7, 2 → 9.
Constraints
0 <= number of nodes <= 10^4 -1000 <= node value <= 1000 Hidden tests include near-max size for this bound; a slower-than-intended solution TLEs.
Examples
Example 1
Input: [1,[2,None,None],[3,None,None]] Expected: 1
Example 2
Input: [4,[2,[3,None,None],[5,None,None]],[9,None,[7,None,None]]] Expected: 15
Example 3
Input: None Expected: 0