
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.




public static int[] sort(int[] old) {
    // Loop for every bit in the integers
    for (int shift = Integer.SIZE - 1; shift > -1; shift--) {
        // The array to put the partially sorted array into
        int[] tmp = new int[old.length];
        // The number of 0s
        int j = 0;
 
        // Move the 0s to the new array, and the 1s to the old one
        for (int i = 0; i < old.length; i++) {
            // If there is a 1 in the bit we are testing, the number will be negative
            boolean move = old[i] << shift >= 0;
 
            // If this is the last bit, negative numbers are actually lower
            if (shift == 0 ? !move : move) {
                tmp[j] = old[i];
                j++;
            } else {
                // It's a 1, so stick it in the old array for now
                old[i - j] = old[i];
            }
        }
 
        // Copy over the 1s from the old array
        for (int i = j; i < tmp.length; i++) {
            tmp[i] = old[i - j];
        }
 
        // And now the tmp array gets switched for another round of sorting
        old = tmp;
    }
 
    return old;
}