问在用于排列的Steinhaus-Johnson-Trotter算法中，输出交换列表的算法是什么？

EN

class Elt(object):
    def __init__(self, dir, name):
        self.dir = dir
        self.name = name

n = 6
p = [Elt(0 if i == 0 else -1, i + 1) for i in range(n)]
while(True):
    print(' '.join(str(i.name) for i in p))
    oldpos = None
    for i in range(n):
        if p[i].dir != 0 and (oldpos is None or p[oldpos].name < p[i].name):
            oldpos = i
    if oldpos is None:
        break
    mover = p[oldpos]
    newpos = oldpos + mover.dir
    p[oldpos] = p[newpos]
    p[newpos] = mover
    print(' '*(oldpos + newpos) + 'X')
    if mover.dir == -1 and (newpos == 0 or p[newpos - 1].name > mover.name):
        mover.dir = 0
    if mover.dir == 1 and (newpos == (n - 1) or p[newpos + 1].name > mover.name):
        mover.dir = 0
    for i in range(newpos):
        if p[i].name > mover.name:
            p[i].dir = 1
    for i in range(newpos, n):
        if p[i].name > mover.name:
            p[i].dir = -1