希尔排序(Java实现)

基本希尔排序，步长为2

public class ShellSort {

    public static <T extends Comparable<? super T>> void sort(T[] arr) {
        for (int len = arr.length, step = len / 2; step >= 1; step /= 2) {
            for (int i = step; i < len; i++) {
                T temp = arr[i];
                int j = i - step;
                for (;j >= 0 && arr[j].compareTo(temp) > 0; j -= step) {
                    arr[j + step] = arr[j];
                }
                arr[j + step] = temp;
            }
        }
    }

    public static void swap(Object arr[], int i, int j) {
        if (i != j) {
            Object temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

    private static void printArr(Object[] arr) {
        for (Object o : arr) {
            System.out.print(o);
            System.out.print("\t");
        }
        System.out.println();
    }

    public static void main(String args[]) {
        Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};
        printArr(arr);//3   5   1   7   2   9   8   0   4   6
        sort(arr);
        printArr(arr);//0   1   2   3   4   5   6   7   8   9
    }
}

　

希尔排序，步长为 【1, 4, 13, 40, 121, 364, 1093, ...】

public class ShellSort {

    public static <T extends Comparable<? super T>> void sort2(T[] arr) {
        for (int len = arr.length, step = len / 2; step >= 1; step /= 2) {
            for (int i = step; i < len; i++) {
                T temp = arr[i];
                int j = i - step;
                for (; j >= 0 && arr[j].compareTo(temp) > 0; j -= step) {
                    arr[j + step] = arr[j];
                }
                arr[j + step] = temp;
            }
        }
    }

    public static <T extends Comparable<? super T>> void sort(T[] arr) {
        int len = arr.length;
        int step = 1;
        while (step < len / 3) {
            step = step * 3 + 1;
        }
        for (; step >= 1; step /= 3) {
            for (int i = step; i < len; i++) {
                T temp = arr[i];
                int j = i - step;
                for (; j >= 0 && arr[j].compareTo(temp) > 0; j -= step) {
                    arr[j + step] = arr[j];
                }
                arr[j + step] = temp;
            }
        }
    }


    public static void swap(Object arr[], int i, int j) {
        if (i != j) {
            Object temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

    private static void printArr(Object[] arr) {
        for (Object o : arr) {
            System.out.print(o);
            System.out.print("\t");
        }
        System.out.println();
    }

    public static void main(String args[]) {
        Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};
        printArr(arr);//3   5   1   7   2   9   8   0   4   6
        sort(arr);
        printArr(arr);//0   1   2   3   4   5   6   7   8   9
    }
}