#!ruby -na a=$F.map(&:to_i) puts ((1..n=a.size).map{n-=f=1 b=a n.downto(1){|i|f*=i b=(1..i).map{|j|b[j]-b[j-1]}} k=b[0]/f a=(1..n).map{|x|a[x-1]-k*x**n} k==0?'':" %+dx^%d"%[k,n]}*'').gsub(/\A \+?|\^1|x\^0/,'').gsub(/1x/,'x')