What is an algorithm?
AnswerA step-by-step procedure for solving a problem
An algorithm is a finite set of clear steps that solves a problem or completes a task.
Coding · Facts & stats
Algo facts & stats
7 fact-checked facts about algorithms, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
What must be true of a list before you can use binary search on it?
AnswerIt must be sorted
Binary search halves the search space each step, which only works on sorted data.
Going deeper
The word 'algorithm' comes from the name of which mathematician?
AnswerAl-Khwarizmi
It derives from the Latinized name of the 9th-century Persian mathematician Muhammad ibn Musa al-Khwarizmi.
What is the time complexity of merge sort?
AnswerO(n log n)
Merge sort splits the list in half repeatedly and merges, taking n log n time in all cases.
Which data structure follows first in, first out (FIFO)?
AnswerQueue
A queue works like a line of people: the first to join is the first served.
Expert level
What is the worst-case time complexity of quicksort?
AnswerO(n²)
Quicksort averages O(n log n) but degrades to O(n²) when pivots split the list very unevenly.
What does Euclid's algorithm compute?
AnswerThe greatest common divisor of two numbers
Euclid's algorithm repeatedly takes remainders to find the largest number dividing both inputs.
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