24. Swap Nodes in Pairs

Use the tabs to read the prompt, implementation, and tests separately. Syntax uses Shiki; tests can be executed on the server with node --test.

Same file as in the repo · ~20s timeout

From file header (JSDoc)

24. Swap Nodes in Pairs
@param {import('../../lib/list-node.js').ListNode | null} head
@returns {import('../../lib/list-node.js').ListNode | null}