Linked List Quiz — Quiz

Question 1

What is the time to access the k-th node of a singly linked list?

O(1)O(k)O(log k)O(k²)

Question 2

When reversing a linked list, why do we save cur.next before changing cur.next = prev?

To count the nodesOtherwise we lose the rest of the listTo make it fasterTo handle cycles

Question 3

The list is 1 → 2 → 3 → 4 → 5. Which node does the fast & slow pointer method return as the middle?

Question 4

Floyd's cycle detection uses…

A hash set of visited nodesA slow pointer (1 step) and a fast pointer (2 steps)Sorting the nodesRecursion

Question 5

What is the main benefit of a dummy (sentinel) node?

It makes the list sortedIt removes special cases when the head might changeIt doubles the speedIt stores the length

Question 6

To remove the N-th node from the end in one pass, you…

Reverse the list twiceMove a fast pointer N steps ahead, then move both until fast reaches the endCount the length with recursionUse binary search

Question 7

What are the time and extra space of iterative linked-list reversal?

O(n) time, O(1) spaceO(n) time, O(n) spaceO(n²) time, O(1) spaceO(log n) time, O(1) space

Question 8Select all that apply

Which steps solve "Palindrome Linked List" in O(1) extra space? (select all that apply)

Find the middle with fast & slow pointersReverse the second halfCompare the two halves node by nodeCopy all values into an array and reverse it