59 lines
1.6 KiB
Lua
59 lines
1.6 KiB
Lua
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local quick_sort = Future:new()
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function quick_sort:sort(A, lo, hi, i)
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if lo >= 0 and lo < hi then
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lt, gt = partition(A, lo, hi) -- Multiple return values
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if #self.state["lt"] >= i and #self.state["gt"] >= i then
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self:sort(A, lo, self.state["lt"][i] - 1, i+1)
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self:sort(A, self.state["gt"][i] + 1, hi, i+1)
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else
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table.insert(self.state["lt"], lt)
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table.insert(self.state["gt"], gt)
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return false
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end
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end
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return true
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end
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function quick_sort:poll(array)
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return self:sort(array, 0, array:size(),0)
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end
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-- Divides array into three partitions
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function partition(A, lo, hi)
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-- Pivot value
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local pivot = A.at((lo + hi) / 2) -- Choose the middle element as the pivot (integer division)
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-- Lesser, equal and greater index
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local lt = lo
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local eq = lo
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local gt = hi
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-- Iterate and compare all elements with the pivot
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while eq <= gt do
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if A[eq] < pivot then
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-- Swap the elements at the equal and lesser indices
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A:swap(eq, lt)
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-- Increase lesser index
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lt = lt + 1
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-- Increase equal index
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eq = eq + 1
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elseif A[eq] > pivot then
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-- Swap the elements at the equal and greater indices
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A:swap(eq, gt)
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-- Decrease greater index
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gt = gt - 1
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else -- if A[eq] = pivot then
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-- Increase equal index
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eq = eq + 1
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end
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end
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-- Return lesser and greater indices
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return lt, gt
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end
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function make_available(sorter_list)
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table.insert(sorter_list, "quick_sort")
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end
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