It's very strange but it seems that even long double precision doesn't enough for this problem. I had function get_x(polyline, y), that calculates x coordinate of polyline on coordinate y. I implemented it through binary searching and then calculating by formula, but that resulted in WA23. Then I made an optimisation: if polyline has integer point with coordinate y: (x, y), I instantly return x.

Edited by author 03.01.2024 20:12