pat.rb

# frozen_string_literal: true

# https://pintia.cn/problem-sets/17/problems/260
# input example: 19 *
# output example:
# *****
#  ***
#   *
#  ***
# *****

n, symbol = gets.chomp.split
n = n.to_i
abort if n < 1
total = row = init = 1
inc = 2
remain = n - init
data = []

loop do
  row += inc
  data << row
  total = data.reduce(0, :+) * inc + init
  break if total > n

  remain = n - total
end

data.pop
width = data.last || 1

output = []
(output << data.reverse << 1 << data).flatten!.map! do |i|
  s = ''
  i.times { |_| s += symbol }
  s
end

output.each do |s|
  printf('%*s', (width - s.length) / 2 + s.length, s)
  printf "\n"
end

puts remain