First clear solution for [old] Non-unique Elements by mozurin - javascript coding challenges

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First solution in Clear category for [old] Non-unique Elements by mozurin

"use strict";

function nonUniqueElements(data)
{
    return data.filter(e => data.filter(k => k == e).length > 1);
}

Sept. 8, 2016

Comments:

rdknight on Jan. 13, 2017, 1:03 p.m.
Could you post a link or provide an explanation of what '=>' operator is doing? II'd like to understand what you're doing here to solve the problem. Thanks

oduvan on Jan. 13, 2017, 2:05 p.m.
I think this is what you are looking for <a href="https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions">https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions</a> It creates a function (ES6 syntax)

rdknight on Jan. 13, 2017, 2:40 p.m.
This is perfect, many thanks

rdknight on Jan. 13, 2017, 2:45 p.m.
Wow, ok I understand now, thanks. Very elegant, nice solution.

KabirKang on Feb. 13, 2017, 5:16 p.m.
I could be wrong, but isn't this O(N^2) since for each element e in the data array it is comparing it to element k?

brubru777 on April 20, 2018, 7:02 p.m.
You're right. This is yet another example of a solution rated on its length but whose efficiency is not good at all.

Paul-Yuchao-Dong on May 3, 2017, 3:11 a.m.
wow!! two filters!

RomainBitard on May 31, 2017, 3:23 p.m.
That's what I was trying to do while discovering the syntax of JS :D Thanks for the code

bluffmf on Jan. 22, 2018, 7:22 a.m.
awesome!

pnusho on March 9, 2018, 4:19 p.m.
Thats Awesome!!

wurst on Nov. 24, 2018, 1:50 a.m.
Hats off to you, love this solution, mine worked but was so long and convoluted. I was thinking about using filter but then dismissed that idea for some reason. Its cleaner but would be easier to read if you used descriptive variable names rather than e and k, though I understand what your doing.

ru-alier on March 13, 2019, 5:13 p.m.
Very complicated logic

aditya-padhi-kbl on Jan. 4, 2020, 11:59 a.m.
Time complexity is O(n^2).

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