希尔排序#demo

public class ShellSort {

    public static void main(String[] args) throws Exception {
        int[] numbers = ArrayTools.getRandomInts(9, -5, 5, true);
        ArrayTools.printInts(numbers);
        ArrayTools.printInts(shellSort(numbers));
    }

    public static int[] shellSort(int[] numbers) {
        int d = numbers.length;
        int temp;
        int j;
        while (true) {
            d = d / 2;
            for (int x = 0; x < d; x++) {
                for (int i = x; i < numbers.length; i += d) {
                    temp = numbers[i];
                    for (j = i; j >= d && temp < numbers[j - d]; j -= d) {
                        numbers[j] = numbers[j - d];
                    }
                    numbers[j] = temp;
                }
            }
            if (d == 1) {
                return numbers;
            }
        }
    }
}

 

    /**
     * @param length
     * @param start
     *            inclusive.
     * @param end
     *            exclusive.
     * @param repeat
     *            repeat elements.
     * @return
     * @throws NumberWrongException
     */
    public static int[] getRandomInts(int length, int start, int end, boolean repeat) throws NumberWrongException {
        if (length < 2)
            throw new NumberWrongException("The length must be larger than 1.");
        if (start >= end)
            throw new NumberWrongException("start must be smaller than end.");
        int range = end - start;
        if (length > range)
            throw new NumberWrongException("length must be smaller than range.");
        Random random = new Random();
        int[] numbers = new int[length];
        if (length * 2 > range) {
            LinkedList<Integer> ll = new LinkedList<Integer>();
            for (int i = start; i < end; i++) {
                ll.add(i);
            }
            numbers = new int[length];
            for (int j = 0; j < length; j++) {
                if (repeat) {
                    numbers[j] = ll.get((int) (random.nextFloat() * ll.size()));
                } else {
                    numbers[j] = ll.remove((int) (random.nextFloat() * ll.size()));
                }
            }
        } else {
            numbers[0] = start + (int) (range * random.nextFloat());
            for (int i = 1; i < length; i++) {
                int temp = start + (int) (range * random.nextFloat());
                int j = 0;
                while (j < i) {
                    if (!repeat && temp == numbers[j]) {
                        temp = start + (int) (range * random.nextFloat());
                        j = 0;
                        continue;
                    }
                    j++;
                }
                numbers[j] = temp;
            }
        }
        return numbers;
    }