AtCoder AGC #010 [Ruby]

agc010-a.rb

n = gets.chomp.to_i
even_ = 0
odd_ = 0
gets.chomp.split(" ").each do |x|
  x = x.to_i
  if x.even? then
    even_ += 1
  else
    odd_ += 1
  end
end
if odd_.odd? then
  puts "NO"
else
  puts "YES"
end

agc010-b.rb

# TLE
n = gets.chomp.to_i
aa = gets.chomp.split(" ").map(&:to_i)
 
while true
  amax = aa.max
  break if aa.any?{|x| x == 0} 
  imax = aa.index(amax) + 1
  s = (imax - 1) % n
  n.times do |i|
    j = (s + i + 1) % n
    aa[j] -= (i + 1)
  end
end
if aa.all?{|x| x == 0} then
  puts "YES"
else
  puts "NO"
end