ri-r(i-1),i=n,n-1,...,2 (依次作,从最后一行开始,下一行减上一行)1 2 3 ...n-1 n1 -1 0 ...0 00 2 -2 ...0 0:::::0 0 0 ...2-n 00 0 0 ...n-1 1-nc1+c2+c3+...+cn (所有列加到第1列)n(n+1)/2 2 3 ...n-1 n0 -1 0 .....