fix quicksort.lua

lua/quicksort.lua

@@ -1,34 +1,25 @@
 
-function partition(array, left, right, pivotIndex)
-	local pivotValue = array[pivotIndex]
-	array[pivotIndex], array[right] = array[right], array[pivotIndex]
-
-	local storeIndex = left
-
-	for i =  left, right-1 do
-    	if array[i] <= pivotValue then
-	        array[i], array[storeIndex] = array[storeIndex], array[i]
-	        storeIndex = storeIndex + 1
+local function quicksort(t, left, right)
+	if right < left then return end
+	local pivot = left
+	for i = left + 1, right do
+		if t[i] <= t[pivot] then
+			if i == pivot + 1 then
+			  t[pivot],t[pivot+1] = t[pivot+1],t[pivot]
+			else
+			  t[pivot],t[pivot+1],t[i] = t[i],t[pivot],t[pivot+1]
+			end
+			pivot = pivot + 1
 		end
-		array[storeIndex], array[right] = array[right], array[storeIndex]
-	end
-
-   return storeIndex
-end
-
-function quicksort(array, left, right)
-	if right > left then
-	    local pivotNewIndex = partition(array, left, right, left)
-	    quicksort(array, left, pivotNewIndex - 1)
-	    quicksort(array, pivotNewIndex + 1, right)
 	end
+	quicksort(t, left, pivot - 1)
+	quicksort(t, pivot + 1, right)
 end
 
-
-array = { 1, 5, 2, 17, 11, 3, 1, 22, 2, 37 }
+local array = { 1, 5, 2, 17, 11, 3, 1, 22, 2, 37 }
 
 quicksort(array, 1, #array)
 
 for _, v in pairs(array) do
 	print(v)
-end
+end