A brief analysis of java Hill sorting (Shell) algorithm

First take an integer d1 less than n as the first increment, and divide all records in the file into d1 groups. All records whose distance is a multiple of dl are placed in the same group. First perform direct insertion sorting within each group; then, take the second increment d2This method is essentially a group insertion method.

Schematic diagram:

##Source code

package com.zc.manythread;
/**
 * 
 * @author 偶my耶
 *
 */
public class ShellSort {
    public static int count = 0;
    public static void shellSort(int[] data) {
        // 计算出最大的h值
        int h = 1;
        while (h <= data.length / 3) {
            h = h * 3 + 1;
        }
        while (h > 0) {
            for (int i = h; i < data.length; i += h) {
                if (data[i] < data[i - h]) {
                    int tmp = data[i];
                    int j = i - h;
                    while (j >= 0 && data[j] > tmp) {
                        data[j + h] = data[j];
                        j -= h;
                    }
                    data[j + h] = tmp;
                    print(data);
                }
            }
            // 计算出下一个h值
            h = (h - 1) / 3;
        }
    }
    public static void print(int[] data) {
        for (int i = 0; i < data.length; i++) {
            System.out.print(data[i] + "\t");
        }
        System.out.println();
    }
    public static void main(String[] args) {
        int[] data = new int[] { 4, 3, 6, 2, 1, 9, 5, 8, 7 };
        print(data);
        shellSort(data);
        print(data);
    }
}

Running results:

Shell sorting is unstable, its space overhead is also O(1), and the time overhead is estimated to be between O(N3/2)~O(N7/6)

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