writing code in a notepad :(

gistfile1.txt

"1001" + "11" ---> "1100"
"1" + "1" ---> "10"

def add(number_one, number_two)
  # "1011" 
  # "1111"
  #  1110"
  ones_digit = number_one[-1]
  
  result = ""
  largest_number = [number_one,number_two].max_by {|num| num.length }
  smallest_number = [number_one,number_two].min_by {|num| num.length }
  largest_index = largest_number.size - 1
  smallest_index = smallest_number.size - 1
  carry = 0
  loop
    larger_digit = largest_number[largest_index]
    smaller_digit = smaller_number[smallest_index]
    sum = one_digit.to_i + two_digit.to_i + carry # -> 1
    carry = 0
    # deal with the carry
    if sum <= 1
      result = sum + result
    elsif sum == 2
      result = "0" + result
      carry = 1
    elsif sum == 3
      result = "1" + result
      carry = 1
    end
    # decrement the index
    index -= 1 # update indices
    # add the carry if carry != 0 && index == -1
    break if index == -1 
  end
  
  result = "1" + result if carry > 0
  result
end



[-1, 10, 8, 2, 5, -3, 4, 9, 0], 9
[-3, -1, 0, 2, 4, 5, 8, 9, 10]

10 + -3 = 7
10 + -1 = 9
9 + 0 = 9 # -> [2, 4, 5, 8]

[2, 4, 5, 8, 9, 10]

10 + 2 = 12
bump the right

def pairs(array, goal)
  # sort
  array = array.sort
  result = []
  right_index = arary.length - 1
  left_index = 0
  loop
    right_digit = array[right_index]
    left_digit = array[left_index]
    sum = right_digit + left_digit
    if sum == goal
      puts right_digit + left_digit
      left_index += 1
      right_index -= 1
    elsif sum < goal
      left_index += 1
    else # > goal
      right_index -= 1
    end
    break if right_index == left_index
  end 
end