希尔排序

希尔排序基本步骤
步骤一：选择适当步长(碰到偶数，则加1变成奇数，以减少相同下标的元素进行重复比较)，进行分组。
步骤二：分另对各分分组进行插入排序。重复步骤一。
步骤三：步长依次减半，当步长为1时，且已进行过插入排序后，数组已有序。

老规矩，直接上图。

代码如下：

package com.collonn.algorithm.sort;/** * SHELL SORT */public class ShellSort {// 打印数组private static void PrintArray(int[] s) {System.out.printf("\n-----------------------------------");System.out.printf("\n下标:");for (int p = 0; p < s.length; p++) {System.out.printf("%3d,", p);}System.out.printf("\n值值:");for (Integer m : s) {System.out.printf("%3d,", m);}System.out.printf("\n-----------------------------------");}/** * 插入排序的变种 *  * @param start 开始下标 * @param step 步长 */private void insertSort(int start, int step, int[] s) {// 大循环int j = start + step;for (; j < s.length; j += step) {int i = j - step;int t = s[j];System.out.printf("\ntail_idx=%d, value=%d", j, t);// 小循环，注意，比较排序是从后向前比较的，找一个较大的值，这样实现算法更直观，更优美。for (; i >= start; i -= step) {System.out.printf("\ncompare, value=%d, idx=%d", t, i);if (t < s[i]) {// 发现较小的数，向后移动s[i + step] = s[i];System.out.printf("\nmove, idx=%d to idx=%d", i, (i + step));} else {// 比前面的第一个数大，则，不用处理if (i == j - step) {System.out.printf("\ndo not need compare others");}// 发现大于等于的数，t放到此位置s[i + step] = t;System.out.printf("\nmove, set value=%d on idx=%d", t, (i + step));break;}PrintArray(s);}System.out.printf("\nmin, idx=%d, start_idx=%d", i, start);if (i < start) {System.out.printf("\nmin set, value=%d, idx=%d", t, (i + step));s[i + step] = t;PrintArray(s);}}}// shell sortpublic void shellSort(int[] s) {// 步长int step = s.length;while (true) {// 步长每次减半，遇到偶数加1变成奇数step = step / 2;if (step % 2 == 0) {step++;}// 每组步长的起始下标for (int start = 0; start < step; start++) {System.out.printf("\n>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=%d，起始下标=%d", step, start);// 对开始下标为j步长为i的分组排序this.insertSort(start, step, s);}// 当步长为1排过序后，数组已有序if (step == 1) {break;}}}public static void main(String[] args) {int[] s = new int[] { 30, 25, 16, 7, 19, 20, 7, 5, 2, 8, 3, 1, 6, 9, 50 };PrintArray(s);ShellSort shellSort = new ShellSort();shellSort.shellSort(s);PrintArray(s);}}

执行步骤如下：

-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值: 30, 25, 16,  7, 19, 20,  7,  5,  2,  8,  3,  1,  6,  9, 50,
-----------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=0
tail_idx=7, value=5
compare, value=5, idx=0
move, idx=0 to idx=7
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值: 30, 25, 16,  7, 19, 20,  7, 30,  2,  8,  3,  1,  6,  9, 50,
-----------------------------------
min, idx=-7, start_idx=0
min set, value=5, idx=0
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5, 25, 16,  7, 19, 20,  7, 30,  2,  8,  3,  1,  6,  9, 50,
-----------------------------------
tail_idx=14, value=50
compare, value=50, idx=7
do not need compare others
move, set value=50 on idx=14
min, idx=7, start_idx=0
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=1
tail_idx=8, value=2
compare, value=2, idx=1
move, idx=1 to idx=8
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5, 25, 16,  7, 19, 20,  7, 30, 25,  8,  3,  1,  6,  9, 50,
-----------------------------------
min, idx=-6, start_idx=1
min set, value=2, idx=1
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2, 16,  7, 19, 20,  7, 30, 25,  8,  3,  1,  6,  9, 50,
-----------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=2
tail_idx=9, value=8
compare, value=8, idx=2
move, idx=2 to idx=9
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2, 16,  7, 19, 20,  7, 30, 25, 16,  3,  1,  6,  9, 50,
-----------------------------------
min, idx=-5, start_idx=2
min set, value=8, idx=2
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  7, 19, 20,  7, 30, 25, 16,  3,  1,  6,  9, 50,
-----------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=3
tail_idx=10, value=3
compare, value=3, idx=3
move, idx=3 to idx=10
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  7, 19, 20,  7, 30, 25, 16,  7,  1,  6,  9, 50,
-----------------------------------
min, idx=-4, start_idx=3
min set, value=3, idx=3
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  3, 19, 20,  7, 30, 25, 16,  7,  1,  6,  9, 50,
-----------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=4
tail_idx=11, value=1
compare, value=1, idx=4
move, idx=4 to idx=11
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  3, 19, 20,  7, 30, 25, 16,  7, 19,  6,  9, 50,
-----------------------------------
min, idx=-3, start_idx=4
min set, value=1, idx=4
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  3,  1, 20,  7, 30, 25, 16,  7, 19,  6,  9, 50,
-----------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=5
tail_idx=12, value=6
compare, value=6, idx=5
move, idx=5 to idx=12
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  3,  1, 20,  7, 30, 25, 16,  7, 19, 20,  9, 50,
-----------------------------------
min, idx=-2, start_idx=5
min set, value=6, idx=5
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  3,  1,  6,  7, 30, 25, 16,  7, 19, 20,  9, 50,
-----------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=7，起始下标=6
tail_idx=13, value=9
compare, value=9, idx=6
do not need compare others
move, set value=9 on idx=13
min, idx=6, start_idx=6
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=3，起始下标=0
tail_idx=3, value=3
compare, value=3, idx=0
move, idx=0 to idx=3
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  5,  2,  8,  5,  1,  6,  7, 30, 25, 16,  7, 19, 20,  9, 50,
-----------------------------------
min, idx=-3, start_idx=0
min set, value=3, idx=0
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  2,  8,  5,  1,  6,  7, 30, 25, 16,  7, 19, 20,  9, 50,
-----------------------------------
tail_idx=6, value=7
compare, value=7, idx=3
do not need compare others
move, set value=7 on idx=6
min, idx=3, start_idx=0
tail_idx=9, value=16
compare, value=16, idx=6
do not need compare others
move, set value=16 on idx=9
min, idx=6, start_idx=0
tail_idx=12, value=20
compare, value=20, idx=9
do not need compare others
move, set value=20 on idx=12
min, idx=9, start_idx=0
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=3，起始下标=1
tail_idx=4, value=1
compare, value=1, idx=1
move, idx=1 to idx=4
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  2,  8,  5,  2,  6,  7, 30, 25, 16,  7, 19, 20,  9, 50,
-----------------------------------
min, idx=-2, start_idx=1
min set, value=1, idx=1
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  1,  8,  5,  2,  6,  7, 30, 25, 16,  7, 19, 20,  9, 50,
-----------------------------------
tail_idx=7, value=30
compare, value=30, idx=4
do not need compare others
move, set value=30 on idx=7
min, idx=4, start_idx=1
tail_idx=10, value=7
compare, value=7, idx=7
move, idx=7 to idx=10
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  1,  8,  5,  2,  6,  7, 30, 25, 16, 30, 19, 20,  9, 50,
-----------------------------------
compare, value=7, idx=4
move, set value=7 on idx=7
min, idx=4, start_idx=1
tail_idx=13, value=9
compare, value=9, idx=10
move, idx=10 to idx=13
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  1,  8,  5,  2,  6,  7,  7, 25, 16, 30, 19, 20, 30, 50,
-----------------------------------
compare, value=9, idx=7
move, set value=9 on idx=10
min, idx=7, start_idx=1
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=3，起始下标=2
tail_idx=5, value=6
compare, value=6, idx=2
move, idx=2 to idx=5
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  1,  8,  5,  2,  8,  7,  7, 25, 16,  9, 19, 20, 30, 50,
-----------------------------------
min, idx=-1, start_idx=2
min set, value=6, idx=2
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  1,  6,  5,  2,  8,  7,  7, 25, 16,  9, 19, 20, 30, 50,
-----------------------------------
tail_idx=8, value=25
compare, value=25, idx=5
do not need compare others
move, set value=25 on idx=8
min, idx=5, start_idx=2
tail_idx=11, value=19
compare, value=19, idx=8
move, idx=8 to idx=11
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  1,  6,  5,  2,  8,  7,  7, 25, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=19, idx=5
move, set value=19 on idx=8
min, idx=5, start_idx=2
tail_idx=14, value=50
compare, value=50, idx=11
do not need compare others
move, set value=50 on idx=14
min, idx=11, start_idx=2
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>步长=1，起始下标=0
tail_idx=1, value=1
compare, value=1, idx=0
move, idx=0 to idx=1
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  3,  3,  6,  5,  2,  8,  7,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
min, idx=-1, start_idx=0
min set, value=1, idx=0
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  3,  6,  5,  2,  8,  7,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
tail_idx=2, value=6
compare, value=6, idx=1
do not need compare others
move, set value=6 on idx=2
min, idx=1, start_idx=0
tail_idx=3, value=5
compare, value=5, idx=2
move, idx=2 to idx=3
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  3,  6,  6,  2,  8,  7,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=5, idx=1
move, set value=5 on idx=2
min, idx=1, start_idx=0
tail_idx=4, value=2
compare, value=2, idx=3
move, idx=3 to idx=4
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  3,  5,  6,  6,  8,  7,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=2, idx=2
move, idx=2 to idx=3
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  3,  5,  5,  6,  8,  7,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=2, idx=1
move, idx=1 to idx=2
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  3,  3,  5,  6,  8,  7,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=2, idx=0
move, set value=2 on idx=1
min, idx=0, start_idx=0
tail_idx=5, value=8
compare, value=8, idx=4
do not need compare others
move, set value=8 on idx=5
min, idx=4, start_idx=0
tail_idx=6, value=7
compare, value=7, idx=5
move, idx=5 to idx=6
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  8,  8,  7, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=7, idx=4
move, set value=7 on idx=5
min, idx=4, start_idx=0
tail_idx=7, value=7
compare, value=7, idx=6
move, idx=6 to idx=7
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  7,  8,  8, 19, 16,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=7, idx=5
move, set value=7 on idx=6
min, idx=5, start_idx=0
tail_idx=8, value=19
compare, value=19, idx=7
do not need compare others
move, set value=19 on idx=8
min, idx=7, start_idx=0
tail_idx=9, value=16
compare, value=16, idx=8
move, idx=8 to idx=9
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  7,  7,  8, 19, 19,  9, 25, 20, 30, 50,
-----------------------------------
compare, value=16, idx=7
move, set value=16 on idx=8
min, idx=7, start_idx=0
tail_idx=10, value=9
compare, value=9, idx=9
move, idx=9 to idx=10
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  7,  7,  8, 16, 19, 19, 25, 20, 30, 50,
-----------------------------------
compare, value=9, idx=8
move, idx=8 to idx=9
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  7,  7,  8, 16, 16, 19, 25, 20, 30, 50,
-----------------------------------
compare, value=9, idx=7
move, set value=9 on idx=8
min, idx=7, start_idx=0
tail_idx=11, value=25
compare, value=25, idx=10
do not need compare others
move, set value=25 on idx=11
min, idx=10, start_idx=0
tail_idx=12, value=20
compare, value=20, idx=11
move, idx=11 to idx=12
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  7,  7,  8,  9, 16, 19, 25, 25, 30, 50,
-----------------------------------
compare, value=20, idx=10
move, set value=20 on idx=11
min, idx=10, start_idx=0
tail_idx=13, value=30
compare, value=30, idx=12
do not need compare others
move, set value=30 on idx=13
min, idx=12, start_idx=0
tail_idx=14, value=50
compare, value=50, idx=13
do not need compare others
move, set value=50 on idx=14
min, idx=13, start_idx=0
-----------------------------------
下标:  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
值值:  1,  2,  3,  5,  6,  7,  7,  8,  9, 16, 19, 20, 25, 30, 50,
-----------------------------------

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