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  1. class Node:
  2.     def __init__(self):
  3.         self.data = None
  4.         self.next = None
  5.         self.prev = None
  6.  
  7. def CreateList():
  8.     front = None
  9.     back = None
  10.     arr = [1,2,3,4,5,6,7]
  11.     for num in arr:
  12.         if front is None:
  13.             c = Node()
  14.             c.data = num
  15.             c.next = None
  16.             c.prev = None
  17.             front = back = c
  18.         else:
  19.             c = Node()
  20.             c.data = num
  21.             c.next = None
  22.             c.prev = back
  23.             back.next = c
  24.             back = c
  25.  
  26.     return [front, back]
  27.  
  28. def display_left(front):
  29.     c = front
  30.     while c:
  31.         print(c.data, end =" ")
  32.         c = c.next
  33.     print()
  34.  
  35. def display_right(back):
  36.     c = back
  37.     while c:
  38.         print(c.data, end =" ")
  39.         c = c.prev
  40.     print()
  41.  
  42. def remove(front, back, remove_node):
  43.  
  44.     if front.data == remove_node:
  45.         tmp = front
  46.         front = front.next
  47.         if front:
  48.             front.prev = None
  49.         del tmp
  50.  
  51.     elif back.data == remove_node:
  52.         tmp = back
  53.         back = back.prev
  54.         if back:
  55.             back.next = None
  56.         del tmp
  57.     else:
  58.         c = front
  59.         while c.data != remove_node:
  60.             c = c.next
  61.         c.prev.next = c.next
  62.         c.next.prev = c.prev
  63.         del c
  64.     return front, back
  65.  
  66. def main():
  67.     list = CreateList()
  68.     front = list[0]
  69.     back = list[1]
  70.     display_left(front)
  71.     display_right(back)
  72.     remove_node = 1
  73.     front, back = remove(front, back, remove_node)
  74.     print("remove:%d\n"%remove_node)
  75.     display_left(front)
  76.     display_right(back)
  77.     remove_node = 7
  78.     front, back = remove(front, back, remove_node)
  79.     print("remove:%d\n"%remove_node)
  80.     display_left(front)
  81.     display_right(back)
  82.     remove_node = 4
  83.     front, back = remove(front, back, remove_node)
  84.     print("remove:%d\n"%remove_node)
  85.     display_left(front)
  86.     display_right(back)
  87.  
  88. if __name__ == "__main__":
  89.     main()
  90.  
Success #stdin #stdout 0.03s 9592KB
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stdin
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Standard input is empty
stdout
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1 2 3 4 5 6 7 
7 6 5 4 3 2 1 
remove:1

2 3 4 5 6 7 
7 6 5 4 3 2 
remove:7

2 3 4 5 6 
6 5 4 3 2 
remove:4

2 3 5 6 
6 5 3 2
https://ideone.com/VDuOYQ
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language:
Python 3 (python  3.9.5)
created:
329 days ago
visibility:
secret

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