Problem Statement

Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints:

With those constraints there are 960 possible starting positions, thus the name of the variant.

The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed using either the chess symbols in Unicode (♔♕♖♗♘), the letters King Queen Rook Bishop kNight, or the corresponding letters in a language other than English.

Let's start with the solution:

chess960() =
{
  my (C = vector(8), i, j, r);

  C[random(4) * 2 + 1] = C[random(4) * 2 + 2] = "B";
  for (i = 1, 3, while (C[r = random(8) + 1],); C[r] = Vec("NNQ")[i]);
  for (i = 1, 8, if (!C[i], C[i] = Vec("RKR")[j++]));
  C
}