64 lines
1.4 KiB
Python
64 lines
1.4 KiB
Python
class Node:
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def __init__(self, data):
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self.data = data
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self.prev = None
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self.next = None
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def create_list(arr):
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if not arr:
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return None
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head = Node(arr[0])
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cur = head
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for x in arr[1:]:
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n = Node(x)
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cur.next = n
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n.prev = cur
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cur = n
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return head
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def print_list(head):
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res = []
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while head:
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res.append(str(head.data))
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head = head.next
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print("Список:", " ".join(res) if res else "null")
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def remove_odd_positions(head):
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index = 1
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cur = head
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new_head = None
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last = None
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while cur:
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nxt = cur.next
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if index % 2 == 0:
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if not new_head:
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new_head = cur
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cur.prev = None
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else:
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last.next = cur
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cur.prev = last
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last = cur
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index += 1
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cur = nxt
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if last:
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last.next = None
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return new_head
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while True:
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try:
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print("\n1 - Ввести список\n0 - Выход")
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cmd = input("Выбор: ")
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if cmd == "0":
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break
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if cmd == "1":
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arr = list(map(int, input("Введите числа: ").split()))
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head = create_list(arr)
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head = remove_odd_positions(head)
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print_list(head)
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except:
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print("Ошибка ввода")
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