AtCoder ABC #053 [Ruby]

abc053-a.rb

x = gets.chomp.to_i
if x < 1200 then
  puts "ABC"
else
  puts "ARC"
end

abc053-b.rb

s = gets.chomp
a = s.index("A")
z = s.rindex("Z")
puts z - a + 1

abc053-c.rb

# AC
n = gets.chomp.to_i
h = Hash.new(0)
gets.chomp.split(" ").each do |a|
  h[a.to_i] += 1
end

n_even = 0
n_odd = 0
h.each do |k, v|
  if v.even? then
    n_even += 1
  else
    n_odd += 1
  end
end
if n_even.even? then
  puts n_odd + n_even
else
  puts n_odd + n_even - 1
end

abc053-d.rb

x = gets.chomp.to_i
d = x / 11
r = x % 11
if r == 0 then
  puts d * 2
elsif r < 7 then
  puts d * 2 + 1
else
  puts (d + 1) * 2
end