How should I practice Cascade Deletion of Target-Valued Leaves?

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

Is Cascade Deletion of Target-Valued Leaves associated with Microsoft?

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

Cascade Deletion of Target-Valued Leaves

Microsoft● MediumINTERNPHONE SCREEN

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Problem statement

Given a binary tree and an integer target, delete every leaf whose value equals target. Repeat this rule when deletion makes another matching node a leaf, until no matching leaf remains. Return the root of the remaining tree.

For this exercise, assume the empty tree remains empty and the root may also be deleted. Preserve the values and relative links of surviving nodes.

Function

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

Examples

Example 1

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

Removing matching leaves can expose another removable matching leaf.

Example 2

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

The entire tree disappears when every node is removable.

Example 3

root = []target = 2return = []

An empty tree remains empty.

Constraints

For this exercise, assume a finite acyclic binary tree containing 0 through 500 nodes.
-10^6 <= node.val <= 10^6. The same bound applies to target.