Khan quick sort

quicksort.jl

# https://rosettacode.org/wiki/Sorting_algorithms/Quicksort#Julia

julia> function quicksort_ex!(A, i=1, j=length(A))
           if j > i
               pivot = A[rand(i:j)] # random element of A
               left, right = i, j
               while left <= right
                   while A[left] < pivot # partition
                       left += 1
                   end
                   while A[right] > pivot # partition
                       right -= 1
                   end
                   if left <= right
                       A[left], A[right] = A[right], A[left]
                       left += 1
                       right -= 1
                   end
               end
               quicksort_ex!(A,i,right)
               quicksort_ex!(A,left,j)
           end
           return A
       end
quicksort_ex! (generic function with 3 methods)

julia> v = rand(-100:100, 100)
100-element Array{Int64,1}:
 -69
  23
 -23
  66
  25
 -58
 -63
 -83
 -58
  63
   ⋮
 -25
 -61
 -51
 -70
 -72
  73
 -92
  43
  24

julia> @time quicksort_ex!(copy(v))
  0.022634 seconds (2.62 k allocations: 155.695 KiB)
100-element Array{Int64,1}:
 -100
 -100
 -100
  -99
  -99
  -99
  -98
  -97
  -94
  -94
    ⋮
   83
   83
   84
   85
   89
   91
   91
   93
   95

julia>