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Lightning rectangle question test cases seems weak or wrong


in this problem (snackdown problem 1)

3 10
0 5
2 3
2 7

picking up any top AC solutions from

gives the result yes on this test case while the correct ans should be no.

some of my verified solutions are :

not all but most of the solutions passed with wrong logic and this case was a strong edge case in it. so many got ac without handling this case. test cases seem to be weak.

asked 09 Dec '18, 14:55

helloworld0001's gravatar image

accept rate: 0%

edited 10 Dec '18, 08:26

Light source at (0 5) lights toward bottom right direction, (2,3) toward top right and (2,7) toward top left.

(09 Dec '18, 16:58) taran_14076★

@taran_1407 still point 1,6 is left dark

(09 Dec '18, 19:12) helloworld00010★

Sorry, I read the coordinates as (0,5),(3,2),(7,2). My Bad

The answer for the test case you mentioned is no.

(10 Dec '18, 00:53) taran_14076★

@taran_1407 I have updated bit details in the question. It seems like the test cases were weak in this question.

(10 Dec '18, 07:55) helloworld00010★

@taran_1407 @helloworld0001 same problem for me my code is getting is getting WA since i consider this case as no but all teams which considered yes are getting an AC. @admin2 @vijju123 can u look into it will be helpful?

(10 Dec '18, 16:18) lokesh20024★

Wow, in a problem based on casework they forgot to put in all cases.

(10 Dec '18, 19:53) meooow ♦6★

@meooow welcome to codechef XD

(10 Dec '18, 19:59) abdullah7685★

@lokesh2002 you don't appear to have submitted a solution to this problem in codechef - did you submit under a team name? The problem described here is the opposite of your claim; this is about a case that isn't tested, so incomplete solutions are getting AC. If you are unexpectedly getting WA, it's more likely your code has an error.

(11 Dec '18, 06:20) joffan5★
showing 5 of 8 show all

So I did not feel like studying for exams and spent my evening analyzing accepted solutions for RECTLIT. I found that out of 363 accepted solutions in C++, only 253 pass the above test case. I did not check the solutions in other languages, however there are only 23 of them. So approximately 30% of all accepted solutions in C++ should get WA. Make of it what you will ¯\_(ツ)_/¯


answered 11 Dec '18, 03:12

meooow's gravatar image

6★meooow ♦
accept rate: 48%

edited 11 Dec '18, 03:15

Just curious, how did you test them all?

(11 Dec '18, 13:11) abdullah7685★

I wrote scripts to fetch all the accepted C++ solutions and run them locally.

(11 Dec '18, 16:22) meooow ♦6★

Oh nice,Is the API open to common public now?

(11 Dec '18, 17:42) abdullah7685★

You wish. I don't think CodeChef API will become public in my lifetime.

(11 Dec '18, 18:05) meooow ♦6★

"An ideal problem has no test data."

alt text


answered 11 Dec '18, 13:40

aryanc403's gravatar image

accept rate: 10%

Lost my chance at winning a t-shirt because of this... One of the Python solutions I've found answers no if there are no points on the perimeter but still got accepted.


answered 11 Dec '18, 18:44

justin97530's gravatar image

accept rate: 0%

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question asked: 09 Dec '18, 14:55

question was seen: 623 times

last updated: 11 Dec '18, 18:44