优化目标：34行78步

参考：https://github.com/atesgoral/hrm-solutions/blob/master/solutions/28-Three-Sort-34.78/47.75-jdashton.asm

基本思路是，不动数字在地毯上的位置，改变outbox顺序：

1. 将前两个数放到 1，3号地毯
2. 3 - 1，如小于零，认为输出是 right 方向，取第三个数，如果比3号还小，那就直接输出，然后输出 3，1
   1. 如果比3号大但是比1号小，输出 3，2，1
   2. 如果比1号大，输出 3，1，2
3. 3 - 1，如大于零，认为输出是 left 方向，取第三个数，如果比1号小，就直接输出，然后输出 1，3
   1. 如果比1号大但是比3号小，输出 1，2，3
   2. 如果比3号大，输出 1，3，2

代码行数还有优化空间，比参考代码多了16行

snippet.asm

JUMP     start
 
r123:
COPYFROM 1
OUTBOX
COPYFROM 2
OUTBOX
COPYFROM 3
OUTBOX
JUMP     start
 
r321:
COPYFROM 3
OUTBOX
COPYFROM 2
OUTBOX
COPYFROM 1
OUTBOX
 
start:
INBOX
COPYTO   1
INBOX
COPYTO   3
SUB      1
JUMPN    right
INBOX
COPYTO   2
SUB      1
JUMPN    left2
ADD      1
SUB      3
JUMPN    r123
COPYFROM 1
OUTBOX
COPYFROM 3
OUTBOX
COPYFROM 2
OUTBOX
JUMP     start
 
right:
INBOX
COPYTO   2
SUB      3
JUMPN    right2
ADD      3
SUB      1
JUMPN    r321
COPYFROM 3
OUTBOX
COPYFROM 1
OUTBOX
COPYFROM 2
OUTBOX
JUMP     start
 
right2:
ADD      3
OUTBOX
COPYFROM 3
OUTBOX
COPYFROM 1
OUTBOX
JUMP     start
 
left2:
ADD      1
OUTBOX
COPYFROM 1
OUTBOX
COPYFROM 3
OUTBOX
JUMP     start

参考：https://github.com/atesgoral/hrm-solutions/blob/master/solutions/28-Three-Sort-34.78/28.115-eiTTio.asm

如何不引入第三个变量交换2个变量的值(a, b)

1. a, b-a
2. b-a+a, b-a
3. b-a+a, b-a+a-b+a

或者

1. a-b, b
2. a-b, b+a-b
3. b+a-b-a+b, b+a-b

snippet.asm

start:
INBOX
COPYTO   0
INBOX
COPYTO   2
INBOX
 
main:
COPYTO   1
SUB      2
JUMPN    c0
COPYTO   1
ADD      2
COPYTO   2
SUB      1
COPYTO   1
 
c0:
COPYFROM 1
SUB      0
JUMPN    switch10
COPYFROM 0
OUTBOX
COPYFROM 1
OUTBOX
COPYFROM 2
OUTBOX
JUMP     start
 
switch10:
COPYTO   1
ADD      0
COPYTO   0
SUB      1
JUMP     main

snippet.asm

JUMP     init
 
out:
COPYFROM 0
OUTBOX
COPYFROM 1
OUTBOX
COPYFROM 2
OUTBOX
 
init:
INBOX
COPYTO   0
COPYTO   1
COPYTO   2
INBOX
SUB      0
JUMPN    start
ADD      0
COPYTO   1
COPYTO   2
 
third:
INBOX
COPYTO   9
SUB      0
JUMPN    start2
ADD      0
SUB      1
JUMPN    insert
ADD      1
COPYTO   2
JUMP     out
 
start:
ADD      0
COPYTO   0
JUMP     third
 
start2:
COPYFROM 0
COPYTO   1
COPYFROM 9
COPYTO   0
JUMP     out
 
insert:
ADD      1
COPYTO   1
JUMP     out

snippet.asm

JUMP     init
 
out:
COPYFROM 0
OUTBOX
COPYFROM 1
OUTBOX
COPYFROM 2
OUTBOX
 
init:
INBOX
COPYTO   0
INBOX
COPYTO   1
INBOX
COPYTO   2
 
main:
SUB      0
JUMPN    switch0
a:
COPYFROM 2
SUB      1
JUMPN    switch1
b:
COPYFROM 1
SUB      0
JUMPN    switch
JUMP     out
 
 
switch0:
COPYFROM 2
COPYTO   3
COPYFROM 0
COPYTO   2
COPYFROM 3
COPYTO   0
COPYFROM 2
JUMP     a
 
switch1:
COPYFROM 2
COPYTO   3
COPYFROM 1
COPYTO   2
COPYFROM 3
COPYTO   1
JUMP     b
 
switch:
COPYFROM 1
COPYTO   3
COPYFROM 0
COPYTO   1
COPYFROM 3
COPYTO   0
JUMP     out