DDCC 2017 予選

ddcc2017-qual-a.rb

s = gets.chomp
if s[0] == s[1] && s[1] != s[2] && s[2] == s[3]
  puts "Yes"
else
  puts "No"
end

ddcc2017-qual-b.rb

a, b, c, d = gets.chomp.split(" ").map(&:to_i)
puts a * 1728 + b * 144 + c * 12 + d

ddcc2017-qual-c.rb

n, c = gets.chomp.split(" ").map(&:to_i)
l = []
n.times do |i|
  l << [gets.chomp.to_i, i]
end
l.sort_by!{|x| x[0]}
ans = n
l.each do |ll|
  x = l.pop
  if x[1] == ll[1]
    break
  elsif ll[0] + x[0] + 1 <= c
    ans -= 1
  else
    redo
  end
end
puts ans