AtCoder AGC #006 [Ruby]

agc006-a.rb

n = gets.chomp.to_i
s = gets.chomp
t = gets.chomp

ncommon = 0
n.downto(1) do |i|
  if s[(n - i)..(n - 1)] == t[0..(i - 1)] then
    ncommon = i
    break
  end
end
puts (n - ncommon) * 2 + ncommon

agc006-b.rb

n, x = gets.chomp.split(" ").map(&:to_i)
if x == 1 || x == 2*n-1 then
  puts "No"
elsif n == 2 then
  puts "Yes"
  puts [1,2,3]
else
  if x == 2 then
    a2 = [x+1, x, x-1, x+2]
  else
    a2 = [x-1, x, x+1, x-2]
  end
  puts "Yes"
  a1 = (1..(2*n-1)).to_a
  a1 -= a2
  puts a1[0..(n-3)] + a2 + a1[(n-2)..(2*n-2-4)]
end