pe18and67.rb

pe18and67.rb

triangle = []
File.open("data.txt").each do |line|
  to_num = line.split.map(&:to_i)
  triangle << to_num
end

def reduce_last_row(triangle)
  row_index = triangle.size - 2
  triangle[row_index].each_with_index do |value,col_index|
    left = triangle[row_index+1][col_index]
    right = triangle[row_index+1][col_index+1]
    triangle[row_index][col_index] = triangle[row_index][col_index] + [left,right].max
  end
  triangle.pop
end

while triangle.size > 1
  reduce_last_row(triangle)
end

p triangle[0][0]