# Convex Hull of Floating-Point Points

## Description

Given planar points with finite floating-point coordinates, compute their convex hull using Andrew's monotone-chain algorithm.

## Input

The verification-case input consists of an array `pts` of `n` points and writable output array `hull`.

## Output

The function produces the number of hull points, with the hull written to `hull` in boundary order.

## Constraints

- $0 \le n \le 50000$ and every arithmetic result required by the comparisons is finite.

## Source

Classical algorithmic problem reconstructed from the verified C artifact.