### AlimA's blog

By AlimA, 9 years ago,

Hi everyone

I got WA on test 5 for problem #151.

This is my code.

Can anyone help me?

UPD: after month I tried to code this problem again, but again WA on test 5 ! :( This is my new code. Can you help me? Thx in advance :).

• +2

 » 9 years ago, # |   +9 when you find acos(angle), try to replace it finding just cosa, and sina = 1. — cos^2(a), may be it is because of the loss of precision... I don't know exactly
•  » » 9 years ago, # ^ |   0 Thank you very much. But when i changed my code as you said, it got WA on test 1!!!!!! I am really confused. I can not find the mistake.
•  » » » 9 years ago, # ^ |   +3 you make some unnecessary actions, firstly you found cos(alfa) then took alfa = acos(alfa), further again cos(alfa), it may be lose a precision; P.S you confused b and c, AB's length is c, AC's length is b
•  » » » » 9 years ago, # ^ |   0 yes you are right, but i had changed it when i resubmitted (new code) and about the other thing: again you are right but i think i have done it rightly. i put point A on the origin and AB on the X axis.
•  » » » » » 9 years ago, # ^ |   0 of course) but the order must be A, B, C; here some fragments from statement: "**|AB|=c, |AC|=b**", "_Write coordinates of point A to first line, coordinates of B to second line and coordinates of C to third line_" That's why the point B will be on the distance c from A, C on the b distance from A;
 » 8 years ago, # |   0 No one helps? :(
 » 8 days ago, # |   +8 After changing my solution output for the test 1 3 2 from Mission impossible to 3 collinear points (degenerate triangle), I got AC instead of WA on test5.