illustrated-algorithms

Learning and science

algorithm visualization

SHOW HN2017

Illustrated Quicksort algorithm

Shown by skidding on Feb 14, 2017. Click the card to turn it over.

187points

48comments

#186of 2,242 in 2017

Top 9%of 2017 by points

How HN took it

MixedNo clear lean

4 positive, 10 neutral or asking, 2 mixed, 6 critical, out of 22 comments about the project. Thread score -0.06.

Design: 2 for, 2 againstExecution: 1 for, 2 againstIdea: 0 for, 2 against

Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.

positive neutral or mixed critical about another commenter or something else the maker

Fruit illustrations are less intuitive than numbers
From 3 comments
- Personally I find https://visualgo.net/ to be more helpful. I don't think the fruits are too intuitive.
  snackai on HN
- I agree. I find https://visualgo.net/sorting to provide easier to understand animations. Also, the fruits are less understandable to me than simple numbers.
  bastijn on HN
- Good work, looks great! I have the following comments, hope you find them useful: * I find counter intuitive that the animation goes up, i think it should go down, but that…
  Rabei on HN
Animation is too fast to follow; no slow mode
From 1 comment
- Looks great. Have an option to slow it down though. I couldn't follow the animation and the code on the right it was going so quickly.
  deanclatworthy on HN
Implementation drops duplicate elements
From 2 comments
- Nice work! One other note, in addition to the comments here: the algorithm as it's currently written will drop repeated elements. You can easily fix that by changing `greater` to…
  bjarnagin on HN
- I may not have parsed your question correctly, so I apologize in advance. Assuming you are asking about what happens to the "equal" elements- Yes, there is a bug in this code. It…
  cmurphycode on HN
Not in-place, unlike real quicksort
From 1 comment
- some constructive feedback: one of the greatest features of quicksort is that it is an in-place algorithm, it doesn't use any additional storage. qsort cleverest trick is to…
  lanna on HN

Add a slow motion or speed control option
From 2 comments
- Looks great. Have an option to slow it down though. I couldn't follow the animation and the code on the right it was going so quickly.
  deanclatworthy on HN
- That would be nice but auto play is good. Just allow 2-3 options for the speed of a tick.
  deanclatworthy on HN
Add per-step and back/forward buttons
From 2 comments
- Sure but it would be nice to step through at your own pace rather than by intricately dragging a mouse and having to hold the click.
  deanclatworthy on HN
- Good work, looks great! I have the following comments, hope you find them useful: * I find counter intuitive that the animation goes up, i think it should go down, but that…
  Rabei on HN
Show in-place partitioning
From 2 comments
- some constructive feedback: one of the greatest features of quicksort is that it is an in-place algorithm, it doesn't use any additional storage. qsort cleverest trick is to…
  lanna on HN
- With so few elements, I think you can perform the in-place swap as one animation. Take the pivot out, put an arrow on the first and last elements in the list, then - if the left…
  Asooka on HN
Allow setting custom initial lists
From 1 comment
- That's snazzy, good work! I found myself wanting to set my own initial order of the list to see what some specific edge cases (already sorted, one element off from being sorted,…
  vinylkey on HN

Why use quicksort rather than mergesort as the example
From 1 comment
- Why do people keep using Quicksort as an example? I find Mergesort to be much more intuitive. And better yet, it has a much better worst-case performance.
  amelius on HN
Is filtering into less and greater faster than a single pass
From 1 comment
- That's amazing. Just two questions 1) on quicksort: ``` const less = list.filter(i => i < pivot); const greater = list.filter(i => i > pivot); ``` Wouldn't this be faster: ```…
  baby on HN

VisuAlgo
From 2 comments
- Personally I find https://visualgo.net/ to be more helpful. I don't think the fruits are too intuitive.
  snackai on HN
- I agree. I find https://visualgo.net/sorting to provide easier to understand animations. Also, the fruits are less understandable to me than simple numbers.
  bastijn on HN
Mike Bostock's animated algorithms
From 1 comment
- This was cool, the highlighted code tour is a great touch. For anyone else who enjoyed this, you might also enjoy this blog post full of animated algorithms by Mike Bostock:…
  notduncansmith on HN
Toptal sorting algorithms visualization
From 1 comment
- This one? https://www.toptal.com/developers/sorting-algorithms
  shric on HN
USF comparison sort visualization
From 1 comment
- Absolutely: https://www.cs.usfca.edu/~galles/visualization/ComparisonSort.html
  liamondrop on HN