202410101644
tags: #linked-list

var swapPairs = function(head) {
	const dummy = new ListNode();
	dummy.next = head;
	let prev = dummy;
	while (prev.next !== null && prev.next.next !== null) {
		const first = prev.next;
		const second = first.next;
		const then = second.next;
		first.next = then;
		second.next = first;
		prev.next = second;
		prev = prev.next.next;
	}
	return dummy.next;
};

Reference

https://leetcode.com/problems/swap-nodes-in-pairs/