AdventOfCode/knot_tying.rb

INPUT = [97,167,54,178,2,11,209,174,119,248,254,0,255,1,64,190]
INPUT2 = "97,167,54,178,2,11,209,174,119,248,254,0,255,1,64,190"
           
def do_knot text
  knot_lol = (0..255).to_a
  skips = 0
  curr_pos = 0
  text.each do |i|
    temp = []
    
    (0...i).each do |j|
      temp << (knot_lol[(curr_pos+j) % 256])
    end
    (0...i).each do |j|
      knot_lol[(curr_pos+i-1-j) % 256] = temp[j]
    end
    curr_pos += skips + i
    skips += 1
  end
  knot_lol
end



           
def do_knot2 text
  knot_lol = (0..255).to_a
  skips = 0
  curr_pos = 0
  (0...64).each do 
    text.each do |i|
      temp = []
      
      (0...i).each do |j|
        temp << (knot_lol[(curr_pos+j) % 256])
      end
      (0...i).each do |j|
        knot_lol[(curr_pos+i-1-j) % 256] = temp[j]
      end
      curr_pos += skips + i
      skips += 1
    end
  end
  knot_lol
end

def dense_hash input
  blocks = input.each_slice(16).to_a
  final_hash = []
  blocks.each do |block|
    hash = block[0]
    block[1..block.size-1].each do |s|
      hash = hash ^ s
    end
    final_hash << hash
  end
  final_hash
end

def knot_hash input
  knot_hashed = []
  input.each do |s|
    a = s.to_s(16)
    if a.size == 1 then a = "0" + a end
    knot_hashed << a
  end
  knot_hashed.join ""
end


# input.each do |size|
#  # p skips+curr_val
 
#   if size > 0 then
#     knot_lol = knot_lol.each_slice(size).to_a
# #    p knot_lol
#     knot_lol[0].reverse!
# #    p knot_lol
#     knot_lol.flatten!
#   end
#   knot_lol = knot_lol.rotate(skips+curr_val)

#   head += (size + [skips, 0].max)
#   head = head % 5
# #  p "head " + knot_lol[head].to_s

  
#   skips += 1
#   curr_val = size
# #  p knot_lol
# end

out = do_knot INPUT
p (out[0] * out[1]).to_s

input_2 = INPUT2.split("").map(&:ord) + [17, 31, 73, 47, 23]
p knot_hash dense_hash do_knot2 input_2