Miodrag Milenkovic wrote: > Very neat, thanks > > Mio > Here's another solution.
Spoiler: If the numbers are p,q,r,s,t, construct the following S_1=|p|+|q|+|r|+|s|+|t| S_2=|p+q|+|q+r|+|r+s|+..... S_3=|p+q+r|+|q+r+s|+... S_4=|p+q+r+s|+|q+r+s+t|+... S_5=|p+q+r+s+t| (or, for symmetry, 5 times this) Then S=S_1+S_2+S_3+S_4+S_5 is positive, and you can show (with some difficulty) that it is reduced by each operation. Best wishes, John ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
