Binary Search - CS50 Shorts

[@GY-yv5cz]

Probably my favourite algorithm. Any time I know a dataset is sorted, I just want to employ this.

[@troyke]

Thank you Doug! As always, a very clear explanation, with visuals to help support your points!

[@omaroats]

Perfect. This was well explained and easy to follow. Thank you Doug ❤︎

[@candicehwt6375]

every time he asked a question, I was like no please don't pick me to answer, I don't know

[@ojalafsenior4757]

Very well elaborated Doug

[@codeklaudia9696]

Thank you for the video :) Sometimes it is hard to find the Middle. In Python 2, all sorts of divisions return an int. In Python 3 we need to use the // operator

[@mandaleswaranthasarathakum3130]

Thanks man helped with my computing test on search and sorts

[@hugger-bd5ij]

Matthew Mcclintic why

[@vk-hm6te]

@Matthew Mcclintic why

[@MR0IAM0WATCHING0U]

@Matthew Mcclintic why

[@matthewmcclintic5488]

Sorry, I don’t know why I said that. I was trying to be funny next to my friend, as you can see with other comments, but it was stupid.

[@matthewmcclintic5488]

I thought the video was very helpful too and it was not my place to say something like that.

[@TheInvestmentCircle]

I wish there were coding examples in these videos :[

[@Dinopeach]

check big-o.io

[@exnihilonihilfit6316]

Ever heard of Google and Wikipedia?

[@random-xl3zm]

odin project ? lets do it hare krishna

[@whatever63644]

I have a question, what if the number of elements in a sub-array were to be an even number instead of an odd number? Do I round it or just take the integer part?

[@ضحكتكتهمنا-ط3ر]

@@kariimnabiil-911 when the number is 5 the middle ==3 in humanity but in code from 0 what I do when the number is big and I don't need code you understand me, please If you understand, please reply me.

[@julianarchila3671]

You use a round function

[@alialparslan2288]

I think it is up to you. It can be a round function, you can take the int value, or you can look through the middle two number separately ( it will not be the best design, but it's possible) or any other idea. The key is finding the best approach. And i guess, your suggestions are good enough

[@ktswjp]

Great job, Dough! Keep it up. You divided this problem to as simple as possible chunks.

[@ilyesbenmalti9402]

How's life bro

[@sithoidinh3891]

Binary search is much more better than linear search!!!

[@mohammadkermani2987]

Awesome! It was a pretty simple explanation and easy to understand. I enjoyed the way he was explaining in detail and showing it visually! thanks a lot

[@LoneWolf5960]

I'm still trying to wrap my head @7:33 how does the looping logic turn to "Repeat until the (sub)array is of size 0" based on the upper right hand table in the corner. What does "(sub)array is of size 0" mean anyway?

[@kitpaovm8537]

when start point is greater than end point, you can inffer that the subarray is size 0

[@theorbit17]

my mans

[@xxRuleZzZxx]

@Matthew Mcclintic le mans 24 hrs

[@deronburton2994]

Does it only work with a linear arrays?

[@Street_Food_Adventuress]

Awesome !! Continue guys !!

[@NinjaJutsu-y4d]

Great content

[@mortimerc317]

thank you

[@swanandpangam]

But why doesn't we calculate the sorting time as it is the necessary prerequisite?

[@abhinvra]

Binary search is used only for sorted arrays.

[@abhinvra]

It's not a sorting algorithm but a searching one.

[@abhinvra]

For example you can make use of a sorting algorithm such as Merge sort to sort the array and then use Binary search to find if an element is present in there.

[@jayant9151]

ajfjeoaiodjkajgd report

[@andreasv9472]

Because they are two separate operations. Maybe you make thousands of searches for each time you make a sort. In practical terms, if you have sorted one billion webpages (if you are google for example), then you only care how quickly you can give search results to the user. You do not sort the webpages each time someone makes a search on google. You sort them once in a while, and then you allow maybe millions of searches on that array until the next time you sort it. So the speed of the search is what matters here, not the speed of the sort as it is likely to be done in advance, and only once in a while.

[@maxim5519]

thanks!

[@sakib2249]

what if array size is 15.

[@LUITEN1]

Would someone elaborate on the Log n part? Why doesnt that log have a base? I get that as long as n increases, so will the lenght of time (in the linear search case) but I dont fully get it..

[@callumross7682]

In math you tend to presume the base is 10 if it is not given

[@exnihilonihilfit6316]

If you go two thirds down this page to the section entitled _"But Sometimes There Is Confusion ... !"_ , you'll see a little discussion of it: www.mathsisfun.com/algebra/logarithms.html But in this case, the base is 2. n=1 log[2](1)=​0 n=2 log[2](2)=1 n=3 log[2](3)=1.58496 n=4 log[2](4)=2 n=5 log[2](5)=2.32192 n=6 log[2](6)=2.58496 n=7 log[2](7)=2.80735 n=8 log[2](8)=3 n=9 log[2](9)=2log[2](3)=3.16992 David Malan talked about it in the lecture (link has timestamp): kzbin.info/www/bejne/nKrOo5-nl7tsra8

[@elia552]

@@callumross7682 for anyone else reading this now, in computer science you presume the log to be 2, NOT 10

[@kieffel7013]

@@elia552 thanks! if the size of the array is 15, in the worst case scenario it should take 4 iterations right?

[@elia552]

@@kieffel7013 honestly I stopped learning coding and computer science and this is gibberish to me

[@krupasankari]

Doug Lloyd really looks like Doug Mcquaid lol

[@TheThirdlevel-un8do]

Nice sir

[@TheThirdlevel-un8do]

Nice teach you

[@nurgisaandasbek]

Super!

[@samuelfey4924]

we go to the middle I understand that perfectly but how do we chouse either right or left? cause we dont know where that number .

[@alim.7841]

Binary search algorithm works for only sorted arrays so if you find in the middle number less than your target you have go right because there you will find bigger numbers, watch this 0:30

[@brendonspears1164]

Bro said everything except show the code

[@2low2rl]

Why does he seem to be annoyed at his imaginary student? lol

[@mashraful5065]

his hair makes me not understand everything I understood

[@ProVishGaming]

Who here is from Mrs.Denna’s class?

[@talhatariqyuluqatdis]

1

[@talhatariqyuluqatdis]

St

[@sachascarabello7843]

bogos binted