5th in Codeforces Round 744 - Facecam + Commentary + Solutions

Рет қаралды 16,252

Күн бұрын

Contest link: codeforces.com/contest/1579
My submissions: codeforces.com/submissions/ga...
Awesome... making a thunderous return to Div. 3's.
Timestamps:
Intro 00:00
A (solving) 00:23
B (solving) 01:37
E1 (solving) 07:03
D (solving) 10:55
C (solving) 15:08
E2 (solving) 25:29
F (solving) 30:48
G (solving) 38:14
Contest review + 4th 50:37
A (solution + code) 56:37
B (solution + code) 1:00:10
C (solution + code) 1:05:21
Dropping to 5th 1:13:28
D (solution) 1:14:21
E1 (solution + code) 1:17:40
D (code) 1:20:25
E2 (solution + code) 1:21:03
F (solution + code) 1:28:52
G (solution + code) 1:42:02
Outro 1:52:23

Пікірлер: 59

@virenkhatri1932 2 жыл бұрын

What a legend! Competed in the contest, came 5th, explained every problem, solution and the code, with 22 minutes sill remaining. hats off

@priyanshsharma5707 2 жыл бұрын

Congratulations for your amazing performance today!

@nileshchandra6435 2 жыл бұрын

I was so glad to see that my technique for E2 was almost same like yours. I read about the less_equal trick in an ordered set on a cf blog, and got lucky.

@ankitkushwaha633 2 жыл бұрын

hey buddy can you give me a link for this

@kapoorsaumitra 2 жыл бұрын

the man, the myth, the legend

@onurcanisler 2 жыл бұрын

You are so good. I mean you performed way better than those who are using double monitors by using a 13 inch macbook.

@GGxEpsilon 2 жыл бұрын

Like?

@josephwong2832 2 жыл бұрын

love these explanations

@faraziqbal9121 2 жыл бұрын

Got my best performance so far! Super elated

@divyanshgupta273 2 жыл бұрын

Awesome explanation for problem G.

@hridayansh7682 Жыл бұрын

Great video, loved it

@sahil8565 2 жыл бұрын

How did you create that compr command ? and also what's your typing speed and thinking speed ?

@RupeshKumar-dg2tn 2 жыл бұрын

Hey Colin. Love your vods. Just up solved G(thanks to you). For problem G, I was thinking the maximum possible width will be 2000. Coz in the worst case, at any moment, we will be in the exact middle of the width(or else we can move to either of the larger halves). I am not sure. Maybe I'm wrong.

@ColinGalen 2 жыл бұрын

Yes, the maximum possible answer is 2000, for the exact reason you mentioned. Now I'm interested... did you submit a guess, or somehow solve G without that fact?

@RupeshKumar-dg2tn 2 жыл бұрын

Yes, it was a guess. Worked out 😅.

@snehalkumar.singh.cse2070 2 жыл бұрын

Awesome! sir.

@justjie1008 2 жыл бұрын

I completely forgot about the fact that D was greedy. Used up a lot of time through 2 pointers. Could've solved it a lot earlier by using priority_queue

@u1gut 2 жыл бұрын

Colin is there a reason you do i++ instead of ++i? Doesn't it save memory and is one op faster?

@ColinGalen 2 жыл бұрын

I'm pretty sure the c++ compiler will optimize it to whichever is better anyway. But it's mostly force of habit, and changing it has never made a difference for me.

@madhurjoshi4113 2 жыл бұрын

can you tell me how you run your text mate please?

@theVSORIGINALs 2 жыл бұрын

i know i m late but just want to know how u got a hint of some gcd concept in F?

@ayoubdkhissi 2 жыл бұрын

dude you're good

@lamihh 2 жыл бұрын

I'm curious do you have/had a a mentor to guide you on your comepetitive programming journey?

@ColinGalen 2 жыл бұрын

No, only friends that I wanted to beat

@Why_I_am_a_theist 2 жыл бұрын

Colin , do you have the habit of thinking while moving around ? Glad to know, because I thought good programmers just sit and think without a whiteboard? Do you use whiteboard for thinking

@ColinGalen 2 жыл бұрын

Yes, pacing helps me a lot as opposed to just sitting down. I use the whiteboard for doing out math and complex examples (and also for demonstrating my thoughts on div. 2 screencasts where I care less about speed), but I can usually visualize stuff pretty well in my head otherwise.

@ColinGalen 2 жыл бұрын

I also like the experience of jumping up and running back to the computer in excitement when I get an idea

@Why_I_am_a_theist 2 жыл бұрын

@@ColinGalen yes..😆

@likhithrkrishna4914 2 жыл бұрын

@@ColinGalen 🥺

@nirajandata 2 жыл бұрын

daily colin

@ron0studios 2 жыл бұрын

Hey colin, was this round harder than usual div. 3 rounds? I managed to solve 3 problems in the last div 3 contest but could only do 1 in this one

@ColinGalen 2 жыл бұрын

I think B and C were pretty heavy implementation-wise, and they were probably harder than the old form of div. 3's. The round author's different for this one, so that probably explains it. I think D and E1 are also worth a try though, even though they're later in the problem order (in particular, look at the solve count on E1)

@ron0studios 2 жыл бұрын

@@ColinGalen ok thanks, Ill try those questions out!

@glaucoa.9214 2 жыл бұрын

How do I make it when I type it to run cp % compr

@thunderstack5365 2 жыл бұрын

Amazing

@harshpatel105 2 жыл бұрын

Awesome colin. I solved 5/8 this time.

@noobygenius6023 2 жыл бұрын

did u reach specialist?

@theHarshPat 2 жыл бұрын

@@noobygenius6023 You can watch first 2 problem solutions on my channel by the way. Going to post more such solutions of CF and leetcode.

@5590priyank 2 жыл бұрын

for F, the trick of appending a + a, if we have a = 111, then a + a = 111111 and gives 6. so should we use this trick only when atleast one 0 is present?

@ColinGalen 2 жыл бұрын

It's fine if it's all 1's, then you know the answer is infinity.

@maxymopirskyi9771 2 жыл бұрын

Thank you for the explanations! Btw, I have encountered problems like D, but never found a good proof about why greedy works. Does anybody have it?

@hardikraj9469 2 жыл бұрын

If you find a good proof, then please tell me too.

@ColinGalen 2 жыл бұрын

I was going to write out something in comments here. But it became super long, so I wrote it in a codeforces comment (notice that the "comment-844901" part isn't highlighted, that's youtube formatting screwing things up. I guess you should copy/paste the link directly instead of clicking on it.) - codeforces.com/blog/entry/95447?#comment-844901

@ColinGalen 2 жыл бұрын

Also, the editorial gives a proof, I think it's pretty good, but a little handwavy.

@maxymopirskyi9771 2 жыл бұрын

That's a really thorough analysis. I think it is very helpful for less skilled participants. Thanks for it and also for your content!

@joaovictormelo6442 2 жыл бұрын

Why the first sample is invalid?

@kshitijbafna 2 жыл бұрын

And I was 1st in the Facebook hackercup at some point, but ended up 2700+

@sobieso 2 жыл бұрын

cracked af

@nirajandata 2 жыл бұрын

omg, you are back !

@wazirbakhtiyar9523 Жыл бұрын

What's your code forces I'd name

@pranjalverma1348 2 жыл бұрын

Solved A

@irispallis Жыл бұрын

Your hair is beautiful besides your coding skills :)

@stv3qbhxjnmmqbw835 2 жыл бұрын

Don't you get annoyed when people ask your age, age when you started cp, blah blah

@advait2943 2 жыл бұрын

How old were u when u got introduced to cp??

@stv3qbhxjnmmqbw835 2 жыл бұрын

I've heard that when he was born he ran off to the nearest computer in the hospital and started solving codeforces problems.

@joaovictormelo6442 2 жыл бұрын

I don't comprehen why best[i][j] = d - 1;

@yasser_hussain 2 жыл бұрын

First viewer.

@GGxEpsilon 2 жыл бұрын

I am not in your friend list. UwU

@ColinGalen 2 жыл бұрын

don't read too much into it