11.rb

require 'pp'
# Step 1. Take grid and turn it into an array
grid = "08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
        49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
        81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
        52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
        22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
        24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
        32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
        67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
        24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
        21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
        78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
        16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
        86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
        19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
        04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
        88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
        04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
        20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
        20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
        01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48"

grid = grid.split(' ').collect { |string| string.to_i }

# Step 2. Figure out the math
# A. Horizontal
#   1. sum first 4 numbers
    sum = grid[0..3].reduce{ |product, n| product * n }
    puts sum
  # 2. sum up each combo of 4 adjacent numbers in first row
    start = 0
    finish = 3
    
    until finish > 19 do
      sum = grid[start..finish].reduce{ |product, n| product * n }
      puts sum
      start += 1
      finish += 1
    end
    # 3. Figure out which combo of 4 has the greatest sum
    start = 0
    finish = 3
    greatest = 0
    
    until finish > 19 do
      sum = grid[start..finish].reduce{ |product, n| product * n }
      greatest = sum if sum > greatest
      start += 1
      finish += 1
    end
    puts greatest
    # 4. Do this for all rows

    def find_largest_product(array)
      start = 0
      finish = 3
      greatest = 0
      
      until finish > 19 || finish > array.size do
        sum = array[start..finish].reduce{ |product, n| product * n }
        greatest = sum if sum > greatest
        start += 1
        finish += 1
      end
      greatest
    end

# turns out you need to make nested arrays
    # puts grid
    until grid[0].is_a? Array
      row = grid.shift(20)
      grid << row
    end

    answers = []
    grid.each do |array|
      answers << find_largest_product(array)
    end
   puts answers.max
# check to see if I can stop, turns out I can't

# B. Vertical
vertical = []
20.times do
  column = []
  grid.each do |row|
    item = row.shift
    column << item
  end
  vertical << column
end

  answers = []
    vertical.each do |array|
      answers << find_largest_product(array)
    end
   puts answers.max
puts 'hey'
# C. Diagonal - down and right
diagonal = []
vertical = 0
horizontal = 16

until vertical > 19 || horizontal > 19 do
 diagonal << grid[vertical][horizontal]
 vertical += 1
 horizontal += 1
end
pp diagonal



# def make_diagonal_array(horizontal_array, vertical, horizontal)
#   diagonal_array = []
#   until vertical > 19 || horizontal > 19 do
#     diagonal_array << horizontal_array[vertical][horizontal]
#     vertical += 1
#     horizontal += 1
#   end
#   diagonal_array
# end

# # pp make_diagonal_array(grid, 0, 0)

# #make it work for all
# diagonal = []
# vertical = 16
# horizontal = 0

# # pp make_diagonal_array(grid, vertical, horizontal)

# until vertical == 0 && horizontal > 16 do
#   diagonal << make_diagonal_array(grid, vertical, horizontal)
#   if vertical > 0
#     vertical -= 1
#   else
#     horizontal += 1
#   end
# end
# pp diagonal



# Left diagonal
def make_diagonal_array(horizontal_array, vertical, horizontal)
  diagonal_array = []
  until vertical > 19 || horizontal < 0 do
    diagonal_array << horizontal_array[vertical][horizontal]
    vertical += 1
    horizontal -= 1
  end
  diagonal_array
end

pp make_diagonal_array(grid, 0, 19)

#make it work for all
diagonal = []
vertical = 0
horizontal = 3

# pp make_diagonal_array(grid, vertical, horizontal)

until vertical > 16 && horizontal == 19 do
diagonal << make_diagonal_array(grid, vertical, horizontal)
  if horizontal <= 18
    horizontal += 1
  else
    vertical += 1
  end
end
pp diagonal





  answers = []
    diagonal.each do |array|
      answers << find_largest_product(array)
    end
   puts answers.max

# # D. Diagonal - down and left