How should I practice Delete Leaves With a Target Value?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Google onsite interview problems in FastPrep.

Is Delete Leaves With a Target Value associated with Google?

FastPrep tags this as a Google onsite interview coding practice problem when the problem catalog has that company and stage context.

Delete Leaves With a Target Value

Google● MediumINTERNONSITE INTERVIEW

Learn

Problem statement

Given a binary tree and an integer target, repeatedly delete every leaf whose value equals target. After deletions, a parent may become a new target-valued leaf and must also be deleted.

Return the final root. Modify and reuse the surviving input nodes.

Function

removeLeafNodes(root: TreeNode, target: int) → TreeNode

Examples

Example 1

root = [1,2,3,2,null,2,4]target = 2return = [1,null,3,null,4]

All target-valued leaves are removed, including the left child after its child disappears.

Example 2

root = [1,3,3,3,2]target = 3return = [1,3,null,null,2]

The left 3 remains because it still has a non-target child.

Example 3

root = [1,2,null,2,null,2]target = 2return = [1]

Deletion cascades upward through the chain of 2-valued nodes.

Example 4

root = []target = 1return = []

An empty tree remains empty.

Constraints

The tree contains between 0 and 100000 nodes.
-10^9 <= node.val, target <= 10^9.