Problem Statement

A round-robin tournament is also known as an all-play-all-tournament; each participant plays every other participant once. For N participants the number of rounds is N-1 if N is an even number. When there are an odd number of participants then each round one contestor has no opponent (AKA as a "bye"). The number of rounds is N in that case. Write a program that prints out a tournament schedule for 12 participants (represented by numbers 1 to 12).

Let's start with the solution:

∇ SCHEDULER N;R;I
  R←(⍳N),(2|N)⍴'-'
  I←0 ⋄ N←⍴(R)
 L:⎕←'ROUND',I←I+1
  ⎕←((N÷2)↑R),[0.5]⌽(N÷2)↓R
  R←(1↑R),1⌽1↓R
  →(I<N-1)/L
∇