hix←{
  X←⍵
  Z←(≢⍵)⍴¯1
  c←{⊂⍵}⌸ ⍺⍺ ⍵
  Z ⊣ {0 ⊣ Z[⍵]←⍵[xix X⌷⍨⊂⍵]}¨ c
}

   x← ⍕¨ ?16e3⍴1e5

   cmpx 'xix x' 'hf¨ hix x'
  xix x     → 4.02E¯2 |   0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕
  hf¨ hix x → 2.58E¯2 | -36% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕

   ≢ c←{⊂⍵}⌸ hf¨ x
1366

   (⌊/, ⌈/, (+⌿÷≢)) ≢¨c
1 38 11.713