Time Complexity · #14 · 2026-04-18

What's the Big-O?

Python ·Difficulty 3/3

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.

n = len(arr). What is the average-case time complexity?

def quickselect(arr, k):
    pivot = arr[len(arr) // 2]
    left = [x for x in arr if x < pivot]
    mid = [x for x in arr if x == pivot]
    right = [x for x in arr if x > pivot]
    if k < len(left):
        return quickselect(left, k)
    elif k < len(left) + len(mid):
        return mid[0]
    else:
        return quickselect(right, k - len(left) - len(mid))

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