使用python实现递归版汉诺塔示例(汉诺塔递归算法)

def disp_sym(num, sym):
        print(sym*num, end=”)

#recusion
def hanoi(a, b, c, n, tray_num):
 if n == 1:
  move_tray(a, c)
  disp(tray_num)
  sleep(0.7)

 else:
  hanoi(a, c, b, n-1, tray_num)
  move_tray(a, c)
  disp(tray_num)
  sleep(0.7)
  hanoi(b, a, c, n-1, tray_num)

def move_tray(a, b):
 for i in a:
  if i != 0:
   for j in b:
    if j != 0:
     b[b.index(j) – 1] = i
     a[a.index(i)] = 0
     return
   b.append(i)
   b.pop(0)
   a[a.index(i)] = 0
   return

def disp(tray_num):
 global a, b, c
 for i in range(tray_num):
  for j in [‘a’, ‘b’, ‘c’]:
   disp_sym(5, ‘ ‘)
   eval(‘disp_sym(tray_num – ‘ + j + “[i], ‘ ‘)”)
   eval(‘disp_sym(‘ + j + “[i], ‘=’)”)
   disp_sym(1, ‘|’)
   eval(‘disp_sym(‘ + j + “[i], ‘=’)”)
   eval(‘disp_sym(tray_num – ‘ + j + “[i], ‘ ‘)”)

  print()

 print(‘—————————————————————————‘)

tray_num=int(input(“Please input the number of trays:”))
tray=[]
for i in range(tray_num):
 tray.append(i + 1)
a=[0]*tray_num
b=a[:]
c=a[:]

a = tray[:]
disp(tray_num)
hanoi(a, b, c, tray_num, tray_num)