How should I practice Filter Linked-List Nodes and Keep Top K?

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

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Filter Linked-List Nodes and Keep Top K

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Problem statement

Traverse a finite singly linked list and consider only nodes whose value is at least minimum. Among those matching nodes, select the k greatest values and return a new linked list containing their values in original input order. The input list is not modified.

Duplicate nodes count separately. If equal values lie at the selection cutoff, choose earlier matching nodes first.
If fewer than k nodes match, return every matching node. If none match or k is zero, return an empty list.

Function

extractTopKMatching(head: ListNode, minimum: int, k: int) → ListNode

Examples

Example 1

head = [4, 9, 4, 8, 4]minimum = 4k = 3return = [4, 9, 8]

The two larger values are 9 and 8. The earliest of three tied 4-valued nodes fills the third slot, and selected values keep list order.

Example 2

head = [2, -1, 7, 7, 5]minimum = 3k = 2return = [7, 7]

Only 7, 7 and 5 pass the threshold; the top two are the two 7-valued nodes.

Example 3

head = [1, 2, 3]minimum = 10k = 2return = []

No node reaches the minimum, so the extracted list is empty.

Example 4

head = []minimum = 0k = 2return = []

An empty input list has no matching nodes.

Constraints

The input list is acyclic and has 0 through 20000 nodes.
Node values and minimum are integers in [-10^9, 10^9].
0 <= k <= 20000.