last lab

labPython/lab17/task_4.py

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+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.prev = self
+        self.next = self
+
+
+def create_barrier_list(arr):
+    barrier = Node(0)
+    last = barrier
+    for x in arr:
+        n = Node(x)
+        n.prev = last
+        n.next = barrier
+        last.next = n
+        barrier.prev = n
+        last = n
+    return barrier
+
+
+def print_list(barrier):
+    cur = barrier.next
+    res = []
+    while cur != barrier:
+        res.append(str(cur.data))
+        cur = cur.next
+    print("Список:", " ".join(res) if res else "пусто")
+
+
+def split(barrier, current):
+    new_barrier = Node(0)
+    if current == barrier:
+        return new_barrier
+    last = barrier.prev
+    new_barrier.next = current
+    new_barrier.prev = last
+    current.prev.next = barrier
+    barrier.prev = current.prev
+    current.prev = new_barrier
+    last.next = new_barrier
+    return new_barrier
+
+
+while True:
+    try:
+        print("\n1 - Ввести список\n0 - Выход")
+        cmd = input("Выбор: ")
+        if cmd == "0":
+            break
+        if cmd == "1":
+            arr = list(map(int, input("Введите числа: ").split()))
+            barrier = create_barrier_list(arr)
+            print_list(barrier)
+            idx = int(input("Индекс текущего элемента (с 1): "))
+            cur = barrier.next
+            for _ in range(idx - 1):
+                if cur != barrier:
+                    cur = cur.next
+            new_barrier = split(barrier, cur)
+            print("Первый список:")
+            print_list(barrier)
+            print("Второй список:")
+            print_list(new_barrier)
+    except:
+        print("Ошибка")