AtCoder ABC #056 [Ruby]

abc056-a.rb

a, b = gets.chomp.split(" ")
if a == "H" then
  if b == "H" then
    ret = "H"
  else
    ret = "D"
  end
else
  if b == "H" then
    ret = "D"
  else
    ret = "H"
  end
end
puts ret

abc056-b.rb

w, a, b = gets.chomp.split(" ").map(&:to_i)
if b + w < a then
  ret = a - (b + w)
elsif a + w < b then
  ret = b - (a + w)
else
  ret = 0
end
puts ret

abc056-c.rb

x = gets.chomp.to_i

sum = 0
i = 1
while true
  if 2 * x <= (1 + i) * i then
    puts i
    exit
  end
  sum += i
  i += 1
end