Project Euler 19

gistfile1.rb

y = 1901
m = 1
d = 1
w = 1 # 0..6 -> Sun..Sat
count = 0

def m31? (m)
  [1,3,5,7,8,10,12].each do |i|
    if m == i
      return true
    end
  end
  return false
end

def yleap? (y)
  if y % 400 == 0
    return true
  elsif y % 100 ==0
    return false
  elsif y % 4 == 0
    return true
  else
    return false
  end
end

loop do
  w = w == 6 ? w = 0 : w += 1
  if d == 1 && w == 0
    count += 1
  end

  d += 1
  if y == 2000 && m == 12
    break
  end
  if d == 32 || (d == 31 && !m31?(m)) || (d == 30 && m == 2) || (d == 29 && m == 2 && !yleap?(y))
    d = 1
    m += 1
  end
  if m == 13
    m = 1
    y += 1
  end
end

puts count # 171