How hard is LeetCode 663. Equal Tree Partition?

LeetCode 663. Equal Tree Partition is rated Medium on LeetCode.

What is the time complexity of LeetCode 663. Equal Tree Partition?

The Python solution on this page runs in O(V+E).

What is the space complexity of LeetCode 663. Equal Tree Partition?

The Python solution on this page uses O(V) auxiliary space.

What topics does LeetCode 663. Equal Tree Partition cover?

LeetCode 663. Equal Tree Partition is tagged Tree, Depth-First Search and Binary Tree on LeetCode.

Is LeetCode 663. Equal Tree Partition a premium problem?

Yes. LeetCode 663. Equal Tree Partition is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

Equal Tree Partition — LeetCode 663 Python Solution

MediumLeetCode PremiumTreeDepth-First SearchBinary Tree

Problem: #663
Pattern: Tree Traversal
Reading time: 4 min
Source: leetcode.com

The problem

Given the root of a binary tree, return true if you can partition the tree into two trees with equal sums of values after removing exactly one edge on the original tree.

Example

Input: root = [5,10,10,null,null,2,3]
Output: true

Python solution

Python

# 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 checkEqualTree(self, root: TreeNode) -> bool:
        def sum(root):
            if root is None:
                return 0
            l, r = sum(root.left), sum(root.right)
            seen.append(l + r + root.val)
            return seen[-1]

        seen = []
        s = sum(root)
        if s % 2 == 1:
            return False
        seen.pop()
        return s // 2 in seen

Complexity

Measure	Complexity
Time	O(V+E)
Space	O(V) auxiliary

Pattern: Tree Traversal

Choose the order — preorder, inorder, postorder, level — and the problem solves itself. LeetCode 663. Equal Tree Partition is filed here because LeetCode tags it Tree and Binary Tree, which is the vocabulary this hub collects.

The tree traversal guide has the Python template for the pattern and the 225 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 663. Equal Tree Partition?: LeetCode 663. Equal Tree Partition is rated Medium on LeetCode.
What is the time complexity of LeetCode 663. Equal Tree Partition?: The Python solution on this page runs in O(V+E).
What is the space complexity of LeetCode 663. Equal Tree Partition?: The Python solution on this page uses O(V) auxiliary space.
What topics does LeetCode 663. Equal Tree Partition cover?: LeetCode 663. Equal Tree Partition is tagged Tree, Depth-First Search and Binary Tree on LeetCode.
Is LeetCode 663. Equal Tree Partition a premium problem?: Yes. LeetCode 663. Equal Tree Partition is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.