
Sorting Algorithm

This is a sorting algorithm.   It may be applied to a set of data in order to sort it.    
For comparing various sorts, see compare sorts.  
For other sorting algorithms,   see sorting algorithms,   or:

O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort


Use the quickselect algorithm on the vector

 [9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.

 Note: Quicksort has a separate task. 


 
Dim Shared As Long array(9), pivote
 
Function QuickPartition (array() As Long, izda As Long, dcha As Long, pivote As Long) As Long
    Dim As Long pivotValue = array(pivote)
    Swap array(pivote), array(dcha)
    Dim As Long indice = izda
    For i As Long = izda To dcha-1
        If array(i) < pivotValue Then
            Swap array(indice), array(i)
            indice += 1
        End If
    Next i
    Swap array(dcha), array(indice)
    Return indice
End Function
 
Function QuickSelect(array() As Long, izda As Long, dcha As Long, k As Long) As Long
    Do
        If izda = dcha Then Return array(izda) : End If
        pivote = izda
        pivote = QuickPartition(array(), izda, dcha, pivote)
        Select Case k
        Case pivote
            Return array(k)
        Case Is < pivote
            dcha = pivote - 1
        Case Is > pivote
            izda = pivote + 1
        End Select
    Loop
End Function
 
Dim As Long a = Lbound(array), b = Ubound(array)
Print "Array desordenado:  ";
For i As Long = a To b
    Read array(i)
    Print array(i);
Next i
Data 9, 8, 7, 6, 5, 0, 1, 2, 3, 4
 
Print !"\n\n   Array ordenado:  ";
For i As Long = a To b
    Print QuickSelect(array(), a, b, i);
Next i
Sleep
 