Lightning rectangle question test cases seems weak or wrong

snackdown
testcases
weak-test-case

#1

in this problem https://www.codechef.com/problems/RECTLIT (snackdown problem 1)

1
3 10
0 5
2 3
2 7

picking up any top AC solutions from

https://www.codechef.com/status/RECTLIT?sort_by=All&sorting_order=asc&language=All&status=15&handle=&Submit=GO

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

some of my verified solutions are :

https://www.codechef.com/viewsolution/21812372

https://www.codechef.com/viewsolution/21842230

https://www.codechef.com/viewsolution/21837549

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.


#2

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)_/¯


#3

“An ideal problem has no test data.”

alt text


#4

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.


#5

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


#6

@taran_1407 still point 1,6 is left dark


#7

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

The answer for the test case you mentioned is no.


#8

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


#9

@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 please.it will be helpful?


#10

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


#11

@meooow welcome to codechef XD


#12

@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.


#13

Just curious, how did you test them all?


#14

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


#15

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


#16

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