devxlogo

InsertionSort – A simple routine with minimal overhead

InsertionSort – A simple routine with minimal overhead

' InsertionSort.  A simple routine with minimal overhead.  Should never be used ' to sort long lists because of its O(N^2) behavior,'  but is the method of choice for sorting short (5-50 key) lists or long lists ' that have been mostly sorted by a faster algorithm.  InsertionSort is faster ' than either Bubble or SelectionSort and should be used anywhere you would ' consider using those.  Sorts in place (no extra memory needed) and is stable ' (preserves the original order of records with equal keys).  Works by creating ' a sorted list at the beginning of the array of keys.  As each unsorted key to ' the right is examined, it is compared back thru the sorted list until the ' right position to insert it is found.  Two versions are given.  pInsertS is ' an indirect (pointerized) version for strings,'  which can be adapted to doubles by changing the declaration of A().  InsertL ' is a direct version for longs, which can be adapted to integers.' ' Speed:  Abysmally slow for anything but short lists.'' Bottom line:  should be used only to finish up for faster sorts with higher ' overhead; for that purpose, this is the sort to choose.' Usage:  Dim S1(L To R) As StringDim P1(L To R) As LongDim L1(L To R) As Long For I = L To R    S1(I) = GetRandomString()    P1(I) = I    L1(I) = GetRandomLong()Next IpInsertS L, R, S1, P1InsertL L, R, L1' CODE:Sub pInsertS(L As Long, R As Long, A() As String, P() As Long)    Dim LP As Long    Dim RP As Long    Dim TMP As Long    Dim T As String    'RP points to the first unsorted key.       For RP = L + 1 To R     'Get the new value.       TMP = P(RP)        T = A(TMP)    'Compare it back thru the sorted part as long as it's bigger.        For LP = RP To L + 1 Step -1            If T < A(P(LP - 1)) Then P(LP) = P(LP - 1) Else Exit For        Next LP    'It's bigger than all keys to the left, so insert it here.        P(LP) = TMP    Next RPEnd SubSub InsertL(L As Long, R As Long, A() As Long)    Dim LP As Long    Dim RP As Long    Dim TMP As Long        For RP = L + 1 To R        TMP = A(RP)        For LP = RP To L + 1 Step -1            If TMP < A(LP - 1) Then A(LP) = A(LP - 1) Else Exit For        Next LP        A(LP) = TMP    Next RPEnd Sub

See also  How College Students Can Shape the Future of Tech Responsibility
devxblackblue

About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

About Our Journalist