MaxDiff←{

     Pairs←{↑⊃,/i,¨¨(i←¯1↓⍳⍵)↓¨⊂⍳⍵}
     MD←{
         p←Pairs≢⍵ ⋄ rm←Pairs ¯2+≢⍵
         ⌈/,(×/⍵[p])-[1]×/⍵[rm⌷⍤0 1⍤2 1⊢(⍳≢⍵)~⍤1⊢p]
     }

⍝ Tests
     42≢MD 5 9 3 4 6:∘∘∘
     10≢MD 1 ¯2 3 ¯4:∘∘∘
     10≢MD ¯3 ¯1 ¯2 ¯4:∘∘∘
     50≢MD 10 2 0 5 1:∘∘∘
     44≢MD 7 8 9 10 10:∘∘∘

     'All tests passed.'

 }