Determining efficiency (Big O Notation) while using arrays in JavaScript

Question

I am struggling to wrap my head around Big O notation and saw the following problem online. I must answer determining whether the following code is O(n), O(n²), O(logn), O(nlogn)

I have watched several videos but am still failing to understand Big O. Can someone please advise to the answer and their methodology for getting there?

function sortSmallestToLargest(entries):
    sorted_entries = {};

    while entries is not empty:
        smallest_entry = entries[0]

        foreach entry in entries:
            if (entry < smallest_entry):
                smallest_entry = entry

        sorted_entries.add(smallest_entry)
        entries.remove(smallest_entry)

    return sorted_entries

Maybe try my answer here: stackoverflow.com/questions/64370621/… — Den-Jason
– Den-Jason, Commented Nov 28, 2020 at 23:26
Could you fix the identation? is sorted_entries.add(smallest_entry) inside the for loop, or perhaps the if? We can't tell. — Countour-Integral
– Countour-Integral, Commented Nov 28, 2020 at 23:28
I've submitted an edit according to how I think it should look - in which case the complexity is O(n^2) — Den-Jason
– Den-Jason, Commented Nov 28, 2020 at 23:31

BlackBrain · Accepted Answer · 2020-11-28 23:31:30Z

2

The algorithm iterates multiple time on 'entries' until it gets empty. first time in the inner loop it iterates n time (assuming entries length is n at start). second time in the inner loop it iterates n-1 time (because one item was removed in the previous iteration). So at the end we have this series of iterations:

n + (n-1) + (n-2) + ... + 1 = n(n+1)/2 = O(n^2)

answered Nov 28, 2020 at 23:31

BlackBrain

1,0298 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Determining efficiency (Big O Notation) while using arrays in JavaScript

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related