Time Complexity · #29 · 2026-05-03

What's the Big-O?

Python ·Difficulty 1/3

How to play

Read the code and pick its time complexity from four Big-O choices. Think about loops, recursion, and hidden costs. Press 1–4 or click to answer.

Singly linked list with n nodes. What is the time complexity?

def reverse(head):
    prev = None
    curr = head
    while curr:
        nxt = curr.next
        curr.next = prev
        prev = curr
        curr = nxt
    return prev

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Press 1 through 4, or tap a numbered choice, to answer. Back to hub