From: Stedwick <philip.brocoum@...>
Date: 2008-02-16T14:34:58+09:00
Subject: My Boggle Solver: I welcome any tips and tricks!

So, I wrote a Boggle solver so that I could win at Scramble and
Griddle on Facebook, and it works great! However, I'm pretty new at
Ruby, so if you know any "rubyisms" or "ruby ways" that would help
clean up my program, feel free to give some pointers =) Code below:

$words = {}
$stems = {}
File.open("enable.txt","r").each do |line|
  word = line.chomp
  $words[word] = true

  0.upto(word.size-2) do |i|
    $stems[word[0..i]] = true
  end
end

puts "Enter Boggle board as a string of letters:"
letters = gets.chomp

$H = 4
$W = 4
if letters.size != $H*$W
  puts "Wrong board size."
  exit
end

i=0
$board = Array.new($H) { Array.new($W) }
0.upto($H-1) do |h|
  0.upto($W-1) do |w|
    $board[h][w] = letters[i..i]
    i+=1
  end
end

$used = Array.new($H) { Array.new($W) { false } }

$found = {}
def solve(h, w, word = '')
  $used[h][w] = true
  word += $board[h][w]
  $found[word] = true if word.size > 2 and $words[word]

  if $stems[word]
    -1.upto(1) do |r|
      -1.upto(1) do |c|
          y = h+r
          x = w+c
          next unless (0..$H-1) === y
          next unless (0..$W-1) === x
          next if $used[y][x]
          solve(y, x, word)
      end
    end
  end

  $used[h][w] = false
end

0.upto($H-1) do |h|
  0.upto($W-1) do |w|
    solve(h,w)
  end
end

found_words = $found.keys.sort_by { |x| x.size }
found_words.each { |x| puts x }
puts
$board.each { |x| puts x.to_s }