UVa 10065 - Useless Tile Packers

Summary
This is a straightforward Convex Hull question.

Explanation
The area wasted is defined in the questions as the area not covered by the points but by the convex hull. So just apply the convex hull algorithm (choose one of them) and calculate the area of the convex hull and call it $$A_c$$. Calculate the area that the points cover and call it $$A$$.

The percentage of wasted space is given by $$\frac{A - A_c}{A_c} * 100%$$

Input
5 0 0 2 0 2 2 1 1 0 2 5 0 0 0 2 1 3 2 2 2 0 0

Output
Tile #1 Wasted Space = 25.00 %

Tile #2 Wasted Space = 0.00 %