Submission #50102025

Source Code Expand

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# お手本 https://atcoder.jp/contests/abc338/submissions/49757867
P = 998244353
class Num
  def self.from_s s
    len = 0
    # 左端(ひだりはし)に起源があり現在地までに終わる値の和(lsum)。@=現在地
    # -
    # --
    # ---@
    lsum = val = 0
    # 左側(ひだりがわ)に起源があり現在地で終わる値の和(rsum)とその累積和(sum)。@=現在地
    # ---@
    #  --@
    #   -@
    sum = rsum = 0
    s.bytes{|d|
      d -= 0x30
 
 
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# お手本 https://atcoder.jp/contests/abc338/submissions/49757867

P = 998244353
class Num
	def self.from_s s
		len = 0

		# 左端(ひだりはし)に起源があり現在地までに終わる値の和(lsum)。@=現在地
		# -
		# --
		# ---@
		lsum = val = 0

		# 左側(ひだりがわ)に起源があり現在地で終わる値の和(rsum)とその累積和(sum)。@=現在地
		# ---@
		#  --@
		#   -@
		sum = rsum = 0

		s.bytes{|d|
			d -= 0x30
			len += 1
			lsum += val = (val*10+d)%P
			sum += rsum = (rsum*10+d*len)%P
		}

		return new len,val,lsum,rsum,sum
	end

	def initialize *args
		@len,@val,@lsum,@rsum,@sum = args.map{ _1%P }
	end

	attr_reader :len,:val,:lsum,:rsum,:sum
	alias :inspect :sum

	def + r
		Num.new(
			@len+r.len,
			@val+r.val,
			@lsum+r.lsum+@val*r.len,
			r.rsum+@rsum+r.val*@len,
			@sum+@rsum*r.len+r.sum+r.lsum*@len
		)
	end
	def * r
		Num.new(
			@len+r.len,
			@val*r.val,
			@lsum+r.lsum*@val,
			r.rsum+@rsum*r.val,
			@sum+r.sum+@rsum*r.lsum
		)
	end
end

_ = Num.method:from_s
p eval gets.gsub(/[1-9]+/){ "_['#$&']" }

Submission Info

Judge Result