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1080. Insufficient Nodes in Root to Leaf Paths

Difficulty Topics

Description

Given the root of a binary tree and an integer limit, delete all insufficient nodes in the tree simultaneously, and return the root of the resulting binary tree.

A node is insufficient if every root to leaf path intersecting this node has a sum strictly less than limit.

A leaf is a node with no children.

 

Example 1:

Input: root = [1,2,3,4,-99,-99,7,8,9,-99,-99,12,13,-99,14], limit = 1
Output: [1,2,3,4,null,null,7,8,9,null,14]

Example 2:

Input: root = [5,4,8,11,null,17,4,7,1,null,null,5,3], limit = 22
Output: [5,4,8,11,null,17,4,7,null,null,null,5]

Example 3:

Input: root = [1,2,-3,-5,null,4,null], limit = -1
Output: [1,null,-3,4]

 

Constraints:

  • The number of nodes in the tree is in the range [1, 5000].
  • -105 <= Node.val <= 105
  • -109 <= limit <= 109

Solution

insufficient-nodes-in-root-to-leaf-paths.py
# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def sufficientSubset(self, root: TreeNode, limit: int) -> TreeNode:
        if root.left == root.right:
            return None if root.val < limit else root

        if root.left:
            root.left = self.sufficientSubset(root.left, limit - root.val)

        if root.right:
            root.right = self.sufficientSubset(root.right, limit - root.val)

        return root if root.left or root.right else None