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from __future__ import annotations

from random import random

class Node:

"""

Treap's node

Treap is a binary tree by value and heap by priority

"""

def __init__(self, value: int | None = None):

self.value = value

self.prior = random()

self.left: Node | None = None

self.right: Node | None = None

def __repr__(self) -> str:

from pprint import pformat

if self.left is None and self.right is None:

return f"'{self.value}: {self.prior:.5}'"

else:

return pformat(

{f"{self.value}: {self.prior:.5}": (self.left, self.right)}, indent=1

)

def __str__(self) -> str:

value = str(self.value) + " "

left = str(self.left or "")

right = str(self.right or "")

return value + left + right

def split(root: Node | None, value: int) -> tuple[Node | None, Node | None]:

"""

We split current tree into 2 trees with value:

Left tree contains all values less than split value.

Right tree contains all values greater or equal, than split value

"""

if root is None or root.value is None: # None tree is split into 2 Nones

return None, None

elif value < root.value:

"""

Right tree's root will be current node.

Now we split(with the same value) current node's left son

Left tree: left part of that split

Right tree's left son: right part of that split

"""

left, root.left = split(root.left, value)

return left, root

else:

"""

Just symmetric to previous case

"""

root.right, right = split(root.right, value)

return root, right

def merge(left: Node | None, right: Node | None) -> Node | None:

"""

We merge 2 trees into one.

Note: all left tree's values must be less than all right tree's

"""

if (not left) or (not right): # If one node is None, return the other

return left or right

elif left.prior < right.prior:

"""

Left will be root because it has more priority

Now we need to merge left's right son and right tree

"""

left.right = merge(left.right, right)

return left

else:

"""

Symmetric as well

"""

right.left = merge(left, right.left)

return right

def insert(root: Node | None, value: int) -> Node | None:

"""

Insert element

Split current tree with a value into left, right,

Insert new node into the middle

Merge left, node, right into root

"""

node = Node(value)

left, right = split(root, value)

return merge(merge(left, node), right)

def erase(root: Node | None, value: int) -> Node | None:

"""

Erase element

Split all nodes with values less into left,

Split all nodes with values greater into right.

Merge left, right

"""

left, right = split(root, value - 1)

_, right = split(right, value)

return merge(left, right)

def inorder(root: Node | None) -> None:

"""

Just recursive print of a tree

"""

if not root: # None

return

else:

inorder(root.left)

print(root.value, end=",")

inorder(root.right)

def interact_treap(root: Node | None, args: str) -> Node | None:

"""

Commands:

+ value to add value into treap

- value to erase all nodes with value

>>> root = interact_treap(None, "+1")

>>> inorder(root)

>>> root = interact_treap(root, "+3 +5 +17 +19 +2 +16 +4 +0")

>>> inorder(root)

0,1,2,3,4,5,16,17,19,

>>> root = interact_treap(root, "+4 +4 +4")

>>> inorder(root)

0,1,2,3,4,4,4,4,5,16,17,19,

>>> root = interact_treap(root, "-0")

>>> inorder(root)

1,2,3,4,4,4,4,5,16,17,19,

>>> root = interact_treap(root, "-4")

>>> inorder(root)

1,2,3,5,16,17,19,

>>> root = interact_treap(root, "=0")

Unknown command

"""

for arg in args.split():

if arg[0] == "+":

root = insert(root, int(arg[1:]))

elif arg[0] == "-":

root = erase(root, int(arg[1:]))

else:

print("Unknown command")

return root

def main() -> None:

"""After each command, program prints treap"""

root = None

print(

"enter numbers to create a tree, + value to add value into treap, "

"- value to erase all nodes with value. 'q' to quit. "

)

args = input()

while args != "q":

root = interact_treap(root, args)

print(root)

args = input()

print("good by!")

if __name__ == "__main__":

import doctest

doctest.testmod()

main()

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