How should I practice Sum Root-to-Leaf Numbers?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Bloomberg LP phone screen problems in FastPrep.

Is Sum Root-to-Leaf Numbers associated with Bloomberg LP?

FastPrep tags this as a Bloomberg LP phone screen coding practice problem when the problem catalog has that company and stage context.

Sum Root-to-Leaf Numbers

Bloomberg LP● MediumNEW GRADPHONE SCREEN

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Problem statement

You are given the root of a binary tree whose nodes each contain one digit from 0 through 9.

Every root-to-leaf path represents a number formed by reading its digits from the root to the leaf. Return the sum of all such numbers.

A leaf is a node with no children.

Function

sumNumbers(root: TreeNode) → int

Examples

Example 1

root = [1,2,3]return = 25

The paths form 12 and 13, whose sum is 25.

Example 2

root = [4,9,0,5,1]return = 1026

The paths form 495, 491, and 40, which sum to 1026.

Example 3

root = [0]return = 0

The only path consists of the digit 0.

Constraints

The tree contains between 1 and 1000 nodes.
0 <= node.val <= 9.
The root has no leading-zero child-path ambiguity; a root value of 0 is allowed.
The sum of all represented numbers fits in a signed 32-bit integer.