Another update from ingydotnet^djgoku

Task/Sorting-algorithms-Merge-sort/Julia/sorting-algorithms-merge-sort.julia

@@ -0,0 +1,42 @@
+function mergesort!(A::AbstractVector)
+    if length(A) <= 1
+        return A
+    end
+    middle = div(length(A), 2)
+    left = mergesort(A[1:middle])
+    right = mergesort(A[middle + 1:end])
+    result = Array(eltype(left), length(left) + length(right))
+    idx = 1
+    @inbounds while !isempty(left) && !isempty(right)
+        if left[1] <= right[1]
+            result[idx] = left[1]
+            left = left[2:end]
+        else
+            result[idx] = right[1]
+            right = right[2:end]
+        end
+        idx += 1
+    end
+    @inbounds while !isempty(left)
+        result[idx] = left[1]
+        left = left[2:end]
+        idx += 1
+    end
+    @inbounds while !isempty(right)
+        result[idx] = right[1]
+        right = right[2:end]
+        idx += 1
+    end
+    for i=1:length(A)
+        A[i] = result[i]
+    end
+    return A
+end
+
+function mergesort(A::AbstractVector)
+    return mergesort!(copy(A))
+end
+
+A = randcycle(10)
+println("unsorted: ", A)
+println("sorted:   ", mergesort(A))