← Complete problem index

PROJECT EULER · #0270

Cutting Squares

Statement only · SolvedOriginal problem ↗

A square piece of paper with integer dimensions N×N is placed with a corner at the origin and two of its sides along the x- and y-axes. Then, we cut it up respecting the following rules:

  • We only make straight cuts between two points lying on different sides of the square, and having integer coordinates.
  • Two cuts cannot cross, but several cuts can meet at the same border point.
  • Proceed until no more legal cuts can be made.

Counting any reflections or rotations as distinct, we call C(N) the number of ways to cut an N×N square. For example, C(1)=2 and C(2)=30 (shown below).

0270_CutSquare.gif

What is C(30)mod108?

Write-up coming later

The complete problem is available here. An approach, code, and answer will be added later.