
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




Task

Sort an integer array with the   radix sort algorithm.

The primary purpose is to complete the characterization of sort algorithms task.




// counting sort of 'a' according to the digit represented by 'exp'
var countSort = Fn.new { |a, exp|
    var n = a.count
    var output = [0] * n
    var count  = [0] * 10
    for (i in 0...n) {
        var t = (a[i]/exp).truncate % 10
        count[t] = count[t] + 1
    }
    for (i in 1..9) count[i] = count[i] + count[i-1]
    for (i in n-1..0) {
        var t = (a[i]/exp).truncate % 10
        output[count[t] - 1] = a[i]
        count[t] = count[t] - 1
    }
    for (i in 0...n) a[i] = output[i]
}
 
// sorts 'a' in place
var radixSort = Fn.new { |a|
    // check for negative elements
    var min = a.reduce { |m, i| (i < m) ? i : m }
    // if there are any, increase all elements by -min
    if (min < 0) (0...a.count).each { |i| a[i] = a[i] - min }
    // now get the maximum to know number of digits
    var max = a.reduce { |m, i| (i > m) ? i : m }
    // do counting sort for each digit
    var exp = 1
    while ((max/exp).truncate > 0) {
        countSort.call(a, exp)
        exp = exp * 10
    }
    // if there were negative elements, reduce all elements by -min
    if (min < 0) (0...a.count).each { |i| a[i] = a[i] + min }
}
 
var aa =  [[4, 65, 2, -31, 0, 99, 2, 83, 782, 1], [170, 45, 75, 90, 2, 24, -802, -66]]
for (a in aa) {
    System.print("Unsorted: %(a)")
    radixSort.call(a)
    System.print("Sorted  : %(a)\n")
}