CS 61B Lecture 21: Hash Tables

[BuckMarley]

imagine if he just scratched his nails down the chalk board. 

[cannykicks]

he could get on my nerves. kinda pompous

[SirAvalord]

Hot teacher lol

[rs4lmno4]

7 mod -3 = -2 but 7 % -3 = 1

% is the remainder operator. % is not a modulus operator.

In java the remainder operator is designed to follow the following identity for all integers a and b such that b is not 0 (since n / 0 is undefined for all n):

(a / b) * b + (a % b) == a

So in the example, 7 % -3, we enter in the following numbers:

(7 / -3) * -3 + (7 % -3) = 7

Integer arithmetic discards partial numbers.

(-2) * -3 + (7 % -3) = 7

6 + (7 % -3) = 7

(7 % -3) = 1

[0x28]

'pus', 'goo'. LOL

[0x28]

If only other lecturers would be like him.

[dacole82]

Dr. Schewchuk is an excellent lecturer! These videos have helped me so much!

[ssjg0ten]

he writes so cool lol

[iMPRE7ed]

Great lecture.

[kprasad]

Thank you, Professor Swag!

[Killable1337]

slow projector screen :P

[vikkinn]

I didn't know John Malkovich was a professor

[licka]

I'm in love.

[jimmyjubejube]

why dont all universities post online lectures.....

[pithikoulis]

@jimmyjubejube because not all professors are open minded I guess.

[0x28]

@jimmyjubejube One of our professors said that it's forbidden to share data to the outside world, including footage/audio.. bah.

[carlisle21yaps]

like the lecture..... funny handwriting nevertheless it helped me a lot!

[mchekin]

Great teacher!

[popDPx]

yay no homework for next friday!

[MuGGs82]

Thanks for the upload. The lecture was a million times better than the lecture I attended in York University !

[awakeTooOften]

This is great! Thanks for putting these online!

[fermixx]

he makes me remind John Malkovich with long hair :P

nice lectures by the way !

[sigimarti]

so what about an associative array??

are asssocitave arrays internally Hashtables...?

for instance (in java script) if I have:

//declare and initialise the associative array (dictionary)

var dic = [];

dic["hello"]="guten tag";

dic["goodbye"]="aufwiedersehen­";

dic["thank you"]="danke shoen";

var translated_word = dic["thank you"];//finds the German translation

... any comments, opinions, answers???

[poonhokong]

i believe associative array or even the HashTable in Java is actually indexed by some tree. Just guessing

[mastermax1989]

@sigimarti associative arrays are like elements in a hash table.

Hash tables are structures used to store them.

[Lioobayoyo]

For those who are looking for Hash Codes (and how to compute them), see the next lecture.

[mtasic1985]

Comments on upper blackboards are so funny :) lol

[kiara2803kiara]

Thanks..The lecture was very informative.

[freetothinkify]

interesting. this is the only one I've really understood of the ones I've listened to.

[MetaBrainX]

Very helpful and nicelly explained :)

Good work!

[elektrosaurus]

This is awesome, definitely helped me out in my data structures class.

[ba2rn3]

rate me 1-10 n