Submission #993577

---

Source Code Expand

#!/usr/bin/ruby
N,M,*X=`dd`.split.map(&:to_i)
h=Hash.new{|h,k|h[k]=[]}
X.each{|e|
	h[e%M]<<e
}
r=0
pairs=[0]*M
(0..M/2).each{|i|
	opp=M-i
	opp=0 if opp==M
	if i==opp
		npairs=h[i].size/2
		pairs[i]=npairs*2
		r+=npairs
	else
		npairs=[h[i].size,h[opp].size].min
		pairs[i]=pairs[opp]=npairs
		r+=npairs
	end
}
(0...M).each{|i|
	s=h[i].group_by{|e|e}.reduce(0){|s,(k,v)|s+v.size/2}
	r+=[(h[i].size-pairs[i])/2,s].min
}
p r

Submission Info

Compile Error

./Main.rb:3: warning: shadowing outer local variable - h
./Main.rb:23: warning: shadowing outer local variable - s
./Main.rb:23: warning: assigned but unused variable - k

Judge Result