99 lines
2.7 KiB
Python
99 lines
2.7 KiB
Python
class Bst_node:
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def __init__(self, item):
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self.item = item
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self.left = None
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self.right = None
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class Queue_node:
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def __init__(self, data):
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self.data = data
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self.next_ptr = None
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class Queue:
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def __init__(self):
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self.head = None
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self.tail = None
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def insert_bst_node(node_ref, value):
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if node_ref[0] is None:
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node_ref[0] = Bst_node(value)
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else:
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if value < node_ref[0].item:
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if node_ref[0].left is None:
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node_ref[0].left = Bst_node(value)
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else:
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insert_bst_node([node_ref[0].left], value)
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elif value > node_ref[0].item:
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if node_ref[0].right is None:
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node_ref[0].right = Bst_node(value)
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else:
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insert_bst_node([node_ref[0].right], value)
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def enqueue(queue, node):
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new_node = Queue_node(node)
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if is_empty(queue.head):
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queue.head = new_node
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else:
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queue.tail.next_ptr = new_node
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queue.tail = new_node
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def dequeue(queue):
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if queue.head is not None:
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node = queue.head.data
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queue.head = queue.head.next_ptr
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if queue.head is None: # If the queue becomes empty
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queue.tail = None
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return node
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return None
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def is_empty(head):
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return head is None
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def remove_all(node_ref):
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if node_ref[0] is not None:
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remove_all([node_ref[0].left])
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remove_all([node_ref[0].right])
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del node_ref[0]
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def level_order_traversal(root):
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queue = Queue()
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temp = root
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if temp is not None:
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enqueue(queue, temp)
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while not is_empty(queue.head):
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temp = dequeue(queue)
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print(temp.item, end=' ')
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if temp.left is not None:
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enqueue(queue, temp.left)
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if temp.right is not None:
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enqueue(queue, temp.right)
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# Main function to run the program.
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if __name__ == "__main__":
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c = 1
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root = [None] # Use a list to allow modification of the root reference
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print("1: Insert an integer into the binary search tree;")
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print("2: Print the level-order traversal of the binary search tree;")
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print("0: Quit;")
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while c != 0:
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c = int(input("Please input your choice(1/2/0): "))
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if c == 1:
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i = int(input("Input an integer that you want to insert into the Binary Search Tree: "))
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insert_bst_node(root, i)
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elif c == 2:
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print("The resulting level-order traversal of the binary search tree is: ", end="")
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level_order_traversal(root[0]) # Pass the actual root node
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print()
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elif c == 0:
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remove_all(root)
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else:
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print("Choice unknown;") |