"""21 disjoint circles in a rectangle of perimeter 4, maximize the sum of radii (EinsteinArena circles-rectangle, MIT). Upstream bug fixed: the perimeter test is exact (Fractions) upstream but the disjointness test compares float sqrt distances; both are exact here.""" from fractions import Fraction from run import Invalid, float_matrix def check(inst, ans): n = inst["n"] c = float_matrix(ans.get("circles"), n, 3, "circles") F = [tuple(Fraction(v) for v in row) for row in c] if any(r <= 0 for _, _, r in F): raise Invalid("radii must be positive") w = max(x + r for x, _, r in F) - min(x - r for x, _, r in F) h = max(y + r for _, y, r in F) - min(y - r for _, y, r in F) if w + h > 2: raise Invalid("bounding rectangle violates width + height <= 2") for i in range(n): xi, yi, ri = F[i] for j in range(i + 1, n): xj, yj, rj = F[j] if (xi - xj) ** 2 + (yi - yj) ** 2 < (ri + rj) ** 2: raise Invalid(f"circles {i} and {j} overlap") return sum(r for _, _, r in c), {}