This notebook was prepared by Donne Martin. Source and license info is on GitHub.

# Challenge Notebook¶

## Constraints¶

• Can we assume we already have a Node class with an insert method?
• Yes
• What should we do with each node when we process it?
• Call an input method visit_func on the node
• Can we assume this fits in memory?
• Yes

## Test Cases¶

### In-Order Traversal¶

• 5, 2, 8, 1, 3 -> 1, 2, 3, 5, 8
• 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5

### Pre-Order Traversal¶

• 5, 2, 8, 1, 3 -> 5, 2, 1, 3, 8
• 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5

### Post-Order Traversal¶

• 5, 2, 8, 1, 3 -> 1, 3, 2, 8, 5
• 1, 2, 3, 4, 5 -> 5, 4, 3, 2, 1

## Algorithm¶

Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.

## Code¶

In [ ]:
%run ../bst/bst.py

In [ ]:
class BstDfs(Bst):

def in_order_traversal(self, node, visit_func):
# TODO: Implement me
pass

def pre_order_traversal(self, node, visit_func):
# TODO: Implement me
pass

def post_order_traversal(self,node, visit_func):
# TODO: Implement me
pass


## Unit Test¶

In [ ]:
%run ../utils/results.py

In [ ]:
# %load test_dfs.py
import unittest

class TestDfs(unittest.TestCase):

def __init__(self, *args, **kwargs):
super(TestDfs, self).__init__()
self.results = Results()

def test_dfs(self):
bst = BstDfs(Node(5))
bst.insert(2)
bst.insert(8)
bst.insert(1)
bst.insert(3)

self.assertEqual(str(self.results), "[1, 2, 3, 5, 8]")
self.results.clear_results()

self.assertEqual(str(self.results), "[5, 2, 1, 3, 8]")
self.results.clear_results()

self.assertEqual(str(self.results), "[1, 3, 2, 8, 5]")
self.results.clear_results()

bst = BstDfs(Node(1))
bst.insert(2)
bst.insert(3)
bst.insert(4)
bst.insert(5)

self.assertEqual(str(self.results), "[1, 2, 3, 4, 5]")
self.results.clear_results()

self.assertEqual(str(self.results), "[1, 2, 3, 4, 5]")
self.results.clear_results()

self.assertEqual(str(self.results), "[5, 4, 3, 2, 1]")

print('Success: test_dfs')

def main():
test = TestDfs()
test.test_dfs()

if __name__ == '__main__':
main()


## Solution Notebook¶

Review the Solution Notebook for a discussion on algorithms and code solutions.