mirror of
https://github.com/donnemartin/interactive-coding-challenges.git
synced 2024-03-22 13:11:13 +08:00
Added binary search tree challenge.
This commit is contained in:
Donne Martin
parent
757eca26f1
commit
a6c7f71379
0
graphs_trees/bst/__init__.py
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0
graphs_trees/bst/__init__.py
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53
graphs_trees/bst/bst.py
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53
graphs_trees/bst/bst.py
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from collections import deque
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class Node(object):
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def __init__(self, data):
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self.data = data
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self.left = None
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self.right = None
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def insert(self, data):
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if data <= self.data:
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if self.left is None:
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self.left = Node(data)
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else:
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self.left.insert(data)
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else:
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if self.right is None:
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self.right = Node(data)
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else:
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self.right.insert(data)
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def in_order_traversal(self, visit_func):
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if self.left is not None:
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self.left.in_order_traversal(visit_func)
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visit_func(self.data)
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if self.right is not None:
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self.right.in_order_traversal(visit_func)
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def pre_order_traversal(self, visit_func):
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visit_func(self.data)
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if self.left is not None:
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self.left.pre_order_traversal(visit_func)
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if self.right is not None:
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self.right.pre_order_traversal(visit_func)
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def post_order_traversal(self, visit_func):
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if self.left is not None:
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self.left.post_order_traversal(visit_func)
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if self.right is not None:
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self.right.post_order_traversal(visit_func)
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visit_func(self.data)
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def bfs(self, visit_func):
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queue = deque()
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queue.append(self)
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while len(queue) > 0:
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node = queue.popleft()
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visit_func(node.data)
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if node.left is not None:
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queue.append(node.left)
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if node.right is not None:
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queue.append(node.right)
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211
graphs_trees/bst/bst_challenge.ipynb
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211
graphs_trees/bst/bst_challenge.ipynb
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@ -0,0 +1,211 @@
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<small><i>This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Challenge Notebook"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Problem: Implement a binary search tree with an insert method.\n",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Constraints\n",
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"\n",
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"* Can we assume we are working with valid integers?\n",
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" * Yes\n",
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"* Can we assume all left descendents <= n < all right descendents?\n",
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" * Yes\n",
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"* For simplicity, can we use just a Node class without a wrapper Tree class?\n",
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" * Yes"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Test Cases\n",
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"\n",
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"### Insert\n",
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"\n",
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"Insert will be tested through the following traversal:\n",
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"\n",
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"### In-Order Traversal (Provided)\n",
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"\n",
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"* 5, 2, 8, 1, 3 -> 1, 2, 3, 5, 8\n",
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"* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Algorithm\n",
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"\n",
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"Refer to the [solution notebook](https://github.com/donnemartin/interactive-coding-challenges/graphs_trees/bst/bst_solution.ipynb). If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Code"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Note: `in_order_traversal` is provided for testing purposes."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class Node(object):\n",
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"\n",
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" def __init__(self, data):\n",
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" # TODO: Implement me\n",
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"\n",
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" def insert(self, data):\n",
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" # TODO: Implement me\n",
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"\n",
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" def in_order_traversal(self, visit_func):\n",
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" if self.left is not None:\n",
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" self.left.in_order_traversal(visit_func)\n",
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" visit_func(self.data)\n",
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" if self.right is not None:\n",
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" self.right.in_order_traversal(visit_func)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Unit Test"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"**The following unit test is expected to fail until you solve the challenge.**"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"%run ../utils/captured_output.py"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"# %load test_bst.py\n",
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"from __future__ import print_function\n",
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"from nose.tools import assert_equal\n",
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"\n",
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"\n",
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"class TestTree(object):\n",
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"\n",
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" def test_tree(self):\n",
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" root = Node(5)\n",
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" root.insert(2)\n",
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" root.insert(8)\n",
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" root.insert(1)\n",
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" root.insert(3)\n",
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"\n",
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" with captured_output() as (out, err):\n",
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" root.in_order_traversal(sys.stdout.write)\n",
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" assert_equal(out.getvalue().strip(), '12358')\n",
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"\n",
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" root = Node(1)\n",
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" root.insert(2)\n",
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" root.insert(3)\n",
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" root.insert(4)\n",
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" root.insert(5)\n",
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"\n",
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" with captured_output() as (out, err):\n",
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" root.in_order_traversal(sys.stdout.write)\n",
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" assert_equal(out.getvalue().strip(), '12345')\n",
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"\n",
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" print('Success: test_tree')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestTree()\n",
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" test.test_tree()\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Solution Notebook\n",
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"\n",
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"Review the [solution notebook](https://github.com/donnemartin/interactive-coding-challenges/graphs_trees/bst/bst_solution.ipynb) for a discussion on algorithms and code solutions."
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 2",
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"language": "python",
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"name": "python2"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 2
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython2",
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"version": "2.7.10"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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238
graphs_trees/bst/bst_solution.ipynb
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238
graphs_trees/bst/bst_solution.ipynb
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@ -0,0 +1,238 @@
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
|
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"source": [
|
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"<small><i>This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Solution Notebook"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
|
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"## Problem: Implement a binary search tree with an insert method.\n",
|
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"\n",
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"* [Constraints](#Constraints)\n",
|
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
|
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"## Constraints\n",
|
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"\n",
|
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"* Can we assume we are working with valid integers?\n",
|
||||
" * Yes\n",
|
||||
"* Can we assume all left descendents <= n < all right descendents?\n",
|
||||
" * Yes\n",
|
||||
"* For simplicity, can we use just a Node class without a wrapper Tree class?\n",
|
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" * Yes"
|
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]
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},
|
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{
|
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"cell_type": "markdown",
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"metadata": {},
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"source": [
|
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"## Test Cases\n",
|
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"\n",
|
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"### Insert\n",
|
||||
"\n",
|
||||
"Insert will be tested through the following traversal:\n",
|
||||
"\n",
|
||||
"### In-Order Traversal (Provided)\n",
|
||||
"\n",
|
||||
"* 5, 2, 8, 1, 3 -> 1, 2, 3, 5, 8\n",
|
||||
"* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5"
|
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]
|
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Algorithm\n",
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"\n",
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"### Insert\n",
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"\n",
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"* If the data is <= the current node's data\n",
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" * If the current node's left child is None, set it to Node(data)\n",
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" * Else, recursively call insert on the left child\n",
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"* Else\n",
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" * If the current node's right child is None, set it to Node(data)\n",
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" * Else, recursively call insert on the right child\n",
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"\n",
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"Complexity:\n",
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"\n",
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"* Time: O(log n)\n",
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"* Space: O(1)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Code"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
|
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"class Node(object):\n",
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"\n",
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" def __init__(self, data):\n",
|
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" self.data = data\n",
|
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" self.left = None\n",
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" self.right = None\n",
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"\n",
|
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" def insert(self, data):\n",
|
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" if data <= self.data:\n",
|
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" if self.left is None:\n",
|
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" self.left = Node(data)\n",
|
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" else:\n",
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" self.left.insert(data)\n",
|
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" else:\n",
|
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" if self.right is None:\n",
|
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" self.right = Node(data)\n",
|
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" else:\n",
|
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" self.right.insert(data)\n",
|
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"\n",
|
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" def in_order_traversal(self, visit_func):\n",
|
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" if self.left is not None:\n",
|
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" self.left.in_order_traversal(visit_func)\n",
|
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" visit_func(self.data)\n",
|
||||
" if self.right is not None:\n",
|
||||
" self.right.in_order_traversal(visit_func)"
|
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]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
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"metadata": {},
|
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"source": [
|
||||
"## Unit Test"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
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"execution_count": 2,
|
||||
"metadata": {
|
||||
"collapsed": false
|
||||
},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"%run ../utils/captured_output.py"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 3,
|
||||
"metadata": {
|
||||
"collapsed": false
|
||||
},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stdout",
|
||||
"output_type": "stream",
|
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"text": [
|
||||
"Overwriting test_bst.py\n"
|
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]
|
||||
}
|
||||
],
|
||||
"source": [
|
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"%%writefile test_bst.py\n",
|
||||
"from __future__ import print_function\n",
|
||||
"from nose.tools import assert_equal\n",
|
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"\n",
|
||||
"\n",
|
||||
"class TestTree(object):\n",
|
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"\n",
|
||||
" def test_tree(self):\n",
|
||||
" root = Node(5)\n",
|
||||
" root.insert(2)\n",
|
||||
" root.insert(8)\n",
|
||||
" root.insert(1)\n",
|
||||
" root.insert(3)\n",
|
||||
"\n",
|
||||
" with captured_output() as (out, err):\n",
|
||||
" root.in_order_traversal(sys.stdout.write)\n",
|
||||
" assert_equal(out.getvalue().strip(), '12358')\n",
|
||||
"\n",
|
||||
" root = Node(1)\n",
|
||||
" root.insert(2)\n",
|
||||
" root.insert(3)\n",
|
||||
" root.insert(4)\n",
|
||||
" root.insert(5)\n",
|
||||
"\n",
|
||||
" with captured_output() as (out, err):\n",
|
||||
" root.in_order_traversal(sys.stdout.write)\n",
|
||||
" assert_equal(out.getvalue().strip(), '12345')\n",
|
||||
"\n",
|
||||
" print('Success: test_tree')\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"def main():\n",
|
||||
" test = TestTree()\n",
|
||||
" test.test_tree()\n",
|
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"\n",
|
||||
"\n",
|
||||
"if __name__ == '__main__':\n",
|
||||
" main()"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 4,
|
||||
"metadata": {
|
||||
"collapsed": false
|
||||
},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stdout",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"Success: test_tree\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"%run -i test_bst.py"
|
||||
]
|
||||
}
|
||||
],
|
||||
"metadata": {
|
||||
"kernelspec": {
|
||||
"display_name": "Python 2",
|
||||
"language": "python",
|
||||
"name": "python2"
|
||||
},
|
||||
"language_info": {
|
||||
"codemirror_mode": {
|
||||
"name": "ipython",
|
||||
"version": 2
|
||||
},
|
||||
"file_extension": ".py",
|
||||
"mimetype": "text/x-python",
|
||||
"name": "python",
|
||||
"nbconvert_exporter": "python",
|
||||
"pygments_lexer": "ipython2",
|
||||
"version": "2.7.10"
|
||||
}
|
||||
},
|
||||
"nbformat": 4,
|
||||
"nbformat_minor": 0
|
||||
}
|
||||
37
graphs_trees/bst/test_bst.py
Normal file
37
graphs_trees/bst/test_bst.py
Normal file
|
|
@ -0,0 +1,37 @@
|
|||
from __future__ import print_function
|
||||
from nose.tools import assert_equal
|
||||
|
||||
|
||||
class TestTree(object):
|
||||
|
||||
def test_tree(self):
|
||||
root = Node(5)
|
||||
root.insert(2)
|
||||
root.insert(8)
|
||||
root.insert(1)
|
||||
root.insert(3)
|
||||
|
||||
with captured_output() as (out, err):
|
||||
root.in_order_traversal(sys.stdout.write)
|
||||
assert_equal(out.getvalue().strip(), '12358')
|
||||
|
||||
root = Node(1)
|
||||
root.insert(2)
|
||||
root.insert(3)
|
||||
root.insert(4)
|
||||
root.insert(5)
|
||||
|
||||
with captured_output() as (out, err):
|
||||
root.in_order_traversal(sys.stdout.write)
|
||||
assert_equal(out.getvalue().strip(), '12345')
|
||||
|
||||
print('Success: test_tree')
|
||||
|
||||
|
||||
def main():
|
||||
test = TestTree()
|
||||
test.test_tree()
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
main()
|
||||
Loading…
Reference in New Issue
Block a user