def test_is_binary_search_tree(self):
""" Construct two trees, a plain one and a binary search tree:
- binary search tree - - non-search-tree -
(3) (3)
/ \ / \
(1) (5) (9) (7)
\ / \ \ / \
(2) (4) (7) (2) (5) (4)
/ \ / \
(6) (8) (10) (6)
"""
n10 = [None, 10, None, None]
n6 = [None, 6, None, None]
n4 = [None, 4, None, None]
n2 = [None, 2, None, None]
n5 = [None, 5, n10, n6]
n10[PARENT] = n5
n6[PARENT] = n5
n7 = [None, 7, n5, n4]
n5[PARENT] = n7
n4[PARENT] = n7
n9 = [None, 9, None, n2]
n2[PARENT] = n9
n3 = [None, 3, n9, n7]
n9[PARENT] = n3
n7[PARENT] = n3
notSearchTree = n3
trueSearchTree = BST.build([3,1,2,5,4,7,8,9]).root
self.assertTrue(BST.is_binary_search_tree(trueSearchTree),
'should detect a correct search tree')
self.assertFalse(BST.is_binary_search_tree(notSearchTree),
'should detect a when a tree is not search tree')
def test_is_binary_search_tree(self):
""" Construct two trees, a plain one and a binary search tree:
- binary search tree - - non-search-tree -
(3) (3)
/ \ / \
(1) (5) (9) (7)
\ / \ \ / \
(2) (4) (7) (2) (5) (4)
/ \ / \
(6) (8) (10) (6)
"""
n10 = [None, 10, None, None]
n6 = [None, 6, None, None]
n4 = [None, 4, None, None]
n2 = [None, 2, None, None]
n5 = [None, 5, n10, n6]
n10[PARENT] = n5
n6[PARENT] = n5
n7 = [None, 7, n5, n4]
n5[PARENT] = n7
n4[PARENT] = n7
n9 = [None, 9, None, n2]
n2[PARENT] = n9
n3 = [None, 3, n9, n7]
n9[PARENT] = n3
n7[PARENT] = n3
notSearchTree = n3
trueSearchTree = BST.build([3, 1, 2, 5, 4, 7, 8, 9]).root
self.assertTrue(BST.is_binary_search_tree(trueSearchTree),
'should detect a correct search tree')
self.assertFalse(BST.is_binary_search_tree(notSearchTree),
'should detect a when a tree is not search tree')
def test_from_sorted_with_an_inballanced_tree(self):
""" Tests construction of a BST from a sorted array. """
a = [1,2]
tree = BST.from_sorted(a)
self.assertTrue(BST.is_binary_search_tree(tree.root),
'should have built a binary search tree')
self.assertEqual(tree.root[KEY], 1)
self.assertEqual(tree.root[SIZE], 2)
self.assertEqual(tree.root[RIGHT][KEY], 2)
self.assertEqual(tree.root[RIGHT][SIZE], 1)
def test_from_sorted_with_an_inballanced_tree(self):
""" Tests construction of a BST from a sorted array. """
a = [1, 2]
tree = BST.from_sorted(a)
self.assertTrue(BST.is_binary_search_tree(tree.root),
'should have built a binary search tree')
self.assertEqual(tree.root[KEY], 1)
self.assertEqual(tree.root[SIZE], 2)
self.assertEqual(tree.root[RIGHT][KEY], 2)
self.assertEqual(tree.root[RIGHT][SIZE], 1)
def test_is_subtree_when_duplicate_key_is_not_immediate_descendant(self):
""" Given the following tree and the lookup subtree:
(3)
/ \
(2) (6) (3)
/ \ \
(3) (7) (5)
\
(5)
"""
tree = BST.build([3, 2, 6, 3, 7, 5, 3])
subtree = BST.build([3, 3])
actual = tree.is_subtree(subtree)
self.assertTrue(actual, 'should discover the correct subtree')
def test_is_subtree_when_duplicate_key_is_not_immediate_descendant(self):
""" Given the following tree and the lookup subtree:
(3)
/ \
(2) (6) (3)
/ \ \
(3) (7) (5)
\
(5)
"""
tree = BST.build([3, 2, 6, 3, 7, 5, 3])
subtree = BST.build([3, 3])
actual = tree.is_subtree(subtree)
self.assertTrue(actual, 'should discover the correct subtree')
def delete_and_splay(self, key):
""" After regular BST delete, the former node's parent is hoisted to
the root.
"""
removed = BST.delete(self, key)
self.splay(removed[PARENT])
return removed
def test_is_subtree_in_case_of_duplicate_root_keys(self):
""" Given the following binary tree:
(4)
/ \
(2) (5)
/
(2)
/
(1)
"""
tree = BST.build([4, 2, 2, 1, 5])
subtree = BST.build([2, 1])
actual = tree.is_subtree(subtree)
self.assertTrue(actual, 'should discover the correct subtree')
def test_is_subtree_in_case_of_duplicate_root_keys(self):
""" Given the following binary tree:
(4)
/ \
(2) (5)
/
(2)
/
(1)
"""
tree = BST.build([4, 2, 2, 1, 5])
subtree = BST.build([2, 1])
actual = tree.is_subtree(subtree)
self.assertTrue(actual, 'should discover the correct subtree')
def delete_and_splay(self, key):
""" After regular BST delete, the former node's parent is hoisted to
the root.
"""
removed = BST.delete(self, key)
self.splay(removed[PARENT])
return removed
def delete_and_reballance(self, key):
# Node is a recently removed leaf.
node = BST.delete(self, key)
if node == None:
return None
ancestor = node
while ancestor != None:
ancestor = ancestor[PARENT]
# Ignore ballanced ancestors.
if -2 < self.get_ballance_factor(ancestor) < 2:
continue
if self.depth(ancestor[LEFT]) > self.depth(ancestor[RIGHT]):
FIRST = LEFT
else:
FIRST = RIGHT
if self.depth(ancestor[FIRST][LEFT]) > self.depth(ancestor[FIRST][RIGHT]):
SECOND = LEFT
else:
SECOND = RIGHT
#import pdb; pdb.set_trace()
self.reballance(ancestor[FIRST][SECOND])
return node
def test_rotate(self):
""" Test the following right rotation, switching 5 and 7.
(3) (3)
/ \ / \
(1) (5) (1) (7)
\ / \ => \ / \
(2) (4) (7) (2) (5) (8)
/ \ / \
(6) (8) (4) (6)
"""
b = BST.build([3, 1, 2, 5, 4, 7, 8, 6])
b.rotate(b.search(5), RIGHT)
root = b.search(3)
node = b.search(5)
child = b.search(7)
self.assertEqual(root[LEFT][KEY], 1, 'root right child unchanged')
self.assertEqual(root[RIGHT][KEY], 7, '7 swapped places with 5')
self.assertEqual(node[PARENT][KEY], 7, '7 new parent of 5')
self.assertEqual(node[LEFT][KEY], 4,
'left child of 5 remains unchanged')
self.assertEqual(node[RIGHT][KEY], 6,
'left child of 7 becomes new ' + 'right child of 5')
self.assertEqual(child[PARENT][KEY], 3, 'new parent of 7 is root')
self.assertEqual(child[LEFT][KEY], 5,
'left child of 7 is now ' + 'its old parent 5')
self.assertEqual(child[RIGHT][KEY], 8,
'7 old right child is unchanged')
def test_select(self):
b = BST.build([3,1,2,5,4])
self.assertEqual(b.select(1)[KEY], 1, '1st elem is 1')
self.assertEqual(b.select(2)[KEY], 2, '2nd elem is 2')
self.assertEqual(b.select(3)[KEY], 3, '3rd elem is 3')
self.assertEqual(b.select(4)[KEY], 4, '4th elem is 4')
self.assertEqual(b.select(5)[KEY], 5, '5th elem is 5')
def test_select(self):
b = BST.build([3, 1, 2, 5, 4])
self.assertEqual(b.select(1)[KEY], 1, '1st elem is 1')
self.assertEqual(b.select(2)[KEY], 2, '2nd elem is 2')
self.assertEqual(b.select(3)[KEY], 3, '3rd elem is 3')
self.assertEqual(b.select(4)[KEY], 4, '4th elem is 4')
self.assertEqual(b.select(5)[KEY], 5, '5th elem is 5')
def test_rotate(self):
""" Test the following right rotation, switching 5 and 7.
(3) (3)
/ \ / \
(1) (5) (1) (7)
\ / \ => \ / \
(2) (4) (7) (2) (5) (8)
/ \ / \
(6) (8) (4) (6)
"""
b = BST.build([3,1,2,5,4,7,8,6])
b.rotate(b.search(5), RIGHT)
root = b.search(3)
node = b.search(5)
child = b.search(7)
self.assertEqual(root[LEFT][KEY], 1, 'root right child unchanged')
self.assertEqual(root[RIGHT][KEY], 7, '7 swapped places with 5')
self.assertEqual(node[PARENT][KEY], 7, '7 new parent of 5')
self.assertEqual(node[LEFT][KEY], 4, 'left child of 5 remains unchanged')
self.assertEqual(node[RIGHT][KEY], 6, 'left child of 7 becomes new '+
'right child of 5')
self.assertEqual(child[PARENT][KEY], 3, 'new parent of 7 is root')
self.assertEqual(child[LEFT][KEY], 5, 'left child of 7 is now '+
'its old parent 5')
self.assertEqual(child[RIGHT][KEY], 8, '7 old right child is unchanged')
def test_rotate_in_isolation(self):
""" Test makes sure the rotation operation works in isolation:
No parent P, no subtrees A,B or C. Here's the tree format:
Schema (for right rotations):
(None) (None)
| |
(2) (3)
/ \ => / \
(None) (3) (2) (None)
/ \ / \
(None) (None) (None) (None)
Schema (for left rotations):
(None) (None)
| |
(3) (2)
/ \ => / \
(2) (None) (A) (3)
/ \ / \
(None) (None) (None) (None)
"""
b1 = BST.build([2,3])
n2 = b1.search(2)
n3 = b1.search(3)
b1.rotate(n2, RIGHT)
self.assertEqual(b1.root[KEY], 3, 'root has changed')
self.assertEqual(n2[PARENT], n3)
self.assertIsNone(n2[LEFT])
self.assertIsNone(n2[RIGHT])
self.assertIsNone(n3[PARENT])
self.assertEqual(n3[LEFT], n2)
self.assertIsNone(n3[RIGHT])
b2 = BST.build([3,2])
n2 = b2.search(2)
n3 = b2.search(3)
b2.rotate(n3, LEFT)
self.assertEqual(b2.root[KEY], 2, 'root has changed')
self.assertIsNone(n2[PARENT])
self.assertIsNone(n2[LEFT])
self.assertEqual(n2[RIGHT], n3)
self.assertEqual(n3[PARENT], n2)
self.assertIsNone(n3[LEFT])
self.assertIsNone(n3[RIGHT])
def test_rotate_in_isolation(self):
""" Test makes sure the rotation operation works in isolation:
No parent P, no subtrees A,B or C. Here's the tree format:
Schema (for right rotations):
(None) (None)
| |
(2) (3)
/ \ => / \
(None) (3) (2) (None)
/ \ / \
(None) (None) (None) (None)
Schema (for left rotations):
(None) (None)
| |
(3) (2)
/ \ => / \
(2) (None) (A) (3)
/ \ / \
(None) (None) (None) (None)
"""
b1 = BST.build([2, 3])
n2 = b1.search(2)
n3 = b1.search(3)
b1.rotate(n2, RIGHT)
self.assertEqual(b1.root[KEY], 3, 'root has changed')
self.assertEqual(n2[PARENT], n3)
self.assertIsNone(n2[LEFT])
self.assertIsNone(n2[RIGHT])
self.assertIsNone(n3[PARENT])
self.assertEqual(n3[LEFT], n2)
self.assertIsNone(n3[RIGHT])
b2 = BST.build([3, 2])
n2 = b2.search(2)
n3 = b2.search(3)
b2.rotate(n3, LEFT)
self.assertEqual(b2.root[KEY], 2, 'root has changed')
self.assertIsNone(n2[PARENT])
self.assertIsNone(n2[LEFT])
self.assertEqual(n2[RIGHT], n3)
self.assertEqual(n3[PARENT], n2)
self.assertIsNone(n3[LEFT])
self.assertIsNone(n3[RIGHT])
def test_rank(self):
b = BST.build([3, 1, 2, 5, 4])
self.assertEqual(b.rank(1), 0, '0 keys smaller than 1')
self.assertEqual(b.rank(2), 1, '1 key smaller than 2')
self.assertEqual(b.rank(3), 2, '2 keys smaller than 3')
self.assertEqual(b.rank(4), 3, '3 keys smaller than 4')
self.assertEqual(b.rank(5), 4, '4 keys smaller than 5')
self.assertIsNone(b.rank(6), 'key 6 does not exist')
def test_rank(self):
b = BST.build([3,1,2,5,4])
self.assertEqual(b.rank(1), 0, '0 keys smaller than 1')
self.assertEqual(b.rank(2), 1, '1 key smaller than 2')
self.assertEqual(b.rank(3), 2, '2 keys smaller than 3')
self.assertEqual(b.rank(4), 3, '3 keys smaller than 4')
self.assertEqual(b.rank(5), 4, '4 keys smaller than 5')
self.assertIsNone(b.rank(6), 'key 6 does not exist')
def test_search(self):
b = BST.build([3, 1, 2, 5, 4])
self.assertIsNotNone(b.search(3), 'should find 3 in the bst')
self.assertIsNotNone(b.search(1), 'should find 1 in the bst')
self.assertIsNotNone(b.search(2), 'should find 2 in the bst')
self.assertIsNotNone(b.search(5), 'should find 5 in the bst')
self.assertIsNotNone(b.search(4), 'should find 4 in the bst')
self.assertIsNone(b.search(10), 'should not find 10 in the bst')
def test_search(self):
b = BST.build([3,1,2,5,4])
self.assertIsNotNone(b.search(3), 'should find 3 in the bst')
self.assertIsNotNone(b.search(1), 'should find 1 in the bst')
self.assertIsNotNone(b.search(2), 'should find 2 in the bst')
self.assertIsNotNone(b.search(5), 'should find 5 in the bst')
self.assertIsNotNone(b.search(4), 'should find 4 in the bst')
self.assertIsNone(b.search(10), 'should not find 10 in the bst')
def test_is_subtree(self):
""" Given the following binary tree:
(3)
/ \
(1) (5)
/ \ / \
(0) (2) (4) (7)
"""
tree = BST.build([3, 1, 0, 2, 5, 4, 7])
subtree1 = BST.build([1, 0, 2]) # Left subtree
subtree2 = BST.build([2]) # A leaf.
subtree3 = BST.build([3, 1, 0, 2, 5, 4, 7]) # The same tree.
subtree4 = BST.build([5, 4, 8]) # Modified right subtree.
self.assertTrue(tree.is_subtree(subtree1), 'the left subtree')
self.assertTrue(tree.is_subtree(subtree2), 'a tree with only leaf')
self.assertTrue(tree.is_subtree(subtree3), 'the same as original tree')
self.assertFalse(tree.is_subtree(subtree4), 'modified right subtree')
def test_is_subtree(self):
""" Given the following binary tree:
(3)
/ \
(1) (5)
/ \ / \
(0) (2) (4) (7)
"""
tree = BST.build([3, 1, 0, 2, 5, 4, 7])
subtree1 = BST.build([1, 0, 2]) # Left subtree
subtree2 = BST.build([2]) # A leaf.
subtree3 = BST.build([3, 1, 0, 2, 5, 4, 7]) # The same tree.
subtree4 = BST.build([5, 4, 8]) # Modified right subtree.
self.assertTrue(tree.is_subtree(subtree1), 'the left subtree')
self.assertTrue(tree.is_subtree(subtree2), 'a tree with only leaf')
self.assertTrue(tree.is_subtree(subtree3), 'the same as original tree')
self.assertFalse(tree.is_subtree(subtree4), 'modified right subtree')
def test_node_size_gets_modified_on_insertion(self):
b = BST.build([3,1,2,5,4])
self.assertEqual(b.root[SIZE], 5, 'root has size of 5')
b.insert(6)
self.assertEqual(b.root[SIZE], 6, 'new root size is now 6')
self.assertEqual(b.search(1)[SIZE], 2, '1 has size 2')
self.assertEqual(b.search(2)[SIZE], 1, '2 has size 1')
self.assertEqual(b.search(3)[SIZE], 6, '3 has size 6')
self.assertEqual(b.search(4)[SIZE], 1, '4 has size 1')
self.assertEqual(b.search(5)[SIZE], 3, '5 has size 3')
self.assertEqual(b.search(6)[SIZE], 1, '6 has size 1')
def insert(self, key):
""" Insert key in the tree maintaining the Red-Black invariants.
Insert using the default BST insert method and color the node in RED.
Args:
key: int, the value of the inserted node.
"""
inserted_node = BST.insert(self, key)
inserted_node.append(RED)
self.insert_case_1(inserted_node)
def test_node_size_gets_modified_on_insertion(self):
b = BST.build([3, 1, 2, 5, 4])
self.assertEqual(b.root[SIZE], 5, 'root has size of 5')
b.insert(6)
self.assertEqual(b.root[SIZE], 6, 'new root size is now 6')
self.assertEqual(b.search(1)[SIZE], 2, '1 has size 2')
self.assertEqual(b.search(2)[SIZE], 1, '2 has size 1')
self.assertEqual(b.search(3)[SIZE], 6, '3 has size 6')
self.assertEqual(b.search(4)[SIZE], 1, '4 has size 1')
self.assertEqual(b.search(5)[SIZE], 3, '5 has size 3')
self.assertEqual(b.search(6)[SIZE], 1, '6 has size 1')
def test_post_order_traversal(self):
""" Running examples:
(3)
/ \
(1) (5)
/ \ / \
(0) (2) (4) (7)
"""
tree = BST.build([3, 1, 0, 2, 5, 4, 7])
expected = [0, 2, 1, 4, 7, 5, 3]
actual = tree.post_order_traversal()
self.assertEqual(actual, expected, 'post-order traversal')
def insert(self, key):
""" Insert key in the tree maintaining the Red-Black invariants.
Insert using the default BST insert method and color the node in RED.
Args:
key: int, the value of the inserted node.
"""
inserted_node = BST.insert(self, key)
inserted_node.append(RED)
self.insert_case_1(inserted_node)
def test_post_order_traversal(self):
""" Running examples:
(3)
/ \
(1) (5)
/ \ / \
(0) (2) (4) (7)
"""
tree = BST.build([3, 1, 0, 2, 5, 4, 7])
expected = [0, 2, 1, 4, 7, 5, 3]
actual = tree.post_order_traversal()
self.assertEqual(actual, expected, 'post-order traversal')
def test_from_sorted(self):
""" Tests construction of a BST from a sorted array. """
a = [1, 2, 3, 4, 5, 5, 6]
tree = BST.from_sorted(a)
self.assertTrue(BST.is_binary_search_tree(tree.root),
'should have built a binary search tree')
self.assertEqual(tree.root[KEY], 4)
self.assertEqual(tree.root[SIZE], 3)
self.assertEqual(tree.root[LEFT][KEY], 2)
self.assertEqual(tree.root[LEFT][SIZE], 2)
self.assertEqual(tree.root[LEFT][LEFT][KEY], 1)
self.assertEqual(tree.root[LEFT][LEFT][SIZE], 1)
self.assertEqual(tree.root[LEFT][RIGHT][KEY], 3)
self.assertEqual(tree.root[LEFT][RIGHT][SIZE], 1)
self.assertEqual(tree.root[RIGHT][KEY], 5)
self.assertEqual(tree.root[RIGHT][SIZE], 2)
self.assertEqual(tree.root[RIGHT][LEFT][KEY], 5)
self.assertEqual(tree.root[RIGHT][LEFT][SIZE], 1)
self.assertEqual(tree.root[RIGHT][RIGHT][KEY], 6)
self.assertEqual(tree.root[RIGHT][RIGHT][SIZE], 1)
def test_join(self):
""" Tests the method to join the current tree with another one. """
bst1 = BST.build([1,3,5])
bst2 = BST.build([2,4,6])
joined = BST.join(bst1, bst2)
self.assertTrue(BST.is_binary_search_tree(joined.root),
'should have built a binary search tree')
self.assertEqual(joined.root[KEY], 3)
self.assertEqual(joined.root[SIZE], 3)
self.assertEqual(joined.root[LEFT][KEY], 1)
self.assertEqual(joined.root[LEFT][SIZE], 2)
self.assertEqual(joined.root[LEFT][RIGHT][KEY], 2)
self.assertEqual(joined.root[LEFT][RIGHT][SIZE], 1)
self.assertEqual(joined.root[RIGHT][KEY], 5)
self.assertEqual(joined.root[RIGHT][SIZE], 2)
self.assertEqual(joined.root[RIGHT][LEFT][KEY], 4)
self.assertEqual(joined.root[RIGHT][LEFT][SIZE], 1)
self.assertEqual(joined.root[RIGHT][RIGHT][KEY], 6)
self.assertEqual(joined.root[RIGHT][RIGHT][SIZE], 1)
def test_diameter(self):
""" Given the following binary search tree:
(3)
/ \
(2) (4)
/ \
(1) (5)
"""
tree = BST.build([3,2,1,4,5])
actual = tree.diameter()
expected = 5
self.assertEqual(actual, expected, 'should return the path with '+
'the max number of vertices')
def test_from_sorted(self):
""" Tests construction of a BST from a sorted array. """
a = [1,2,3,4,5,5,6]
tree = BST.from_sorted(a)
self.assertTrue(BST.is_binary_search_tree(tree.root),
'should have built a binary search tree')
self.assertEqual(tree.root[KEY], 4)
self.assertEqual(tree.root[SIZE], 3)
self.assertEqual(tree.root[LEFT][KEY], 2)
self.assertEqual(tree.root[LEFT][SIZE], 2)
self.assertEqual(tree.root[LEFT][LEFT][KEY], 1)
self.assertEqual(tree.root[LEFT][LEFT][SIZE], 1)
self.assertEqual(tree.root[LEFT][RIGHT][KEY], 3)
self.assertEqual(tree.root[LEFT][RIGHT][SIZE], 1)
self.assertEqual(tree.root[RIGHT][KEY], 5)
self.assertEqual(tree.root[RIGHT][SIZE], 2)
self.assertEqual(tree.root[RIGHT][LEFT][KEY], 5)
self.assertEqual(tree.root[RIGHT][LEFT][SIZE], 1)
self.assertEqual(tree.root[RIGHT][RIGHT][KEY], 6)
self.assertEqual(tree.root[RIGHT][RIGHT][SIZE], 1)
def test_join(self):
""" Tests the method to join the current tree with another one. """
bst1 = BST.build([1, 3, 5])
bst2 = BST.build([2, 4, 6])
joined = BST.join(bst1, bst2)
self.assertTrue(BST.is_binary_search_tree(joined.root),
'should have built a binary search tree')
self.assertEqual(joined.root[KEY], 3)
self.assertEqual(joined.root[SIZE], 3)
self.assertEqual(joined.root[LEFT][KEY], 1)
self.assertEqual(joined.root[LEFT][SIZE], 2)
self.assertEqual(joined.root[LEFT][RIGHT][KEY], 2)
self.assertEqual(joined.root[LEFT][RIGHT][SIZE], 1)
self.assertEqual(joined.root[RIGHT][KEY], 5)
self.assertEqual(joined.root[RIGHT][SIZE], 2)
self.assertEqual(joined.root[RIGHT][LEFT][KEY], 4)
self.assertEqual(joined.root[RIGHT][LEFT][SIZE], 1)
self.assertEqual(joined.root[RIGHT][RIGHT][KEY], 6)
self.assertEqual(joined.root[RIGHT][RIGHT][SIZE], 1)
def insert(self, key):
""" Insert a node into the data structure.
Args:
key: int, the value to insert in the tree.
Returns:
A list representing the newly inserted node. Format:
"""
node = BST.insert(self, key)
self.reballance(node)
return node
def test_diameter(self):
""" Given the following binary search tree:
(3)
/ \
(2) (4)
/ \
(1) (5)
"""
tree = BST.build([3, 2, 1, 4, 5])
actual = tree.diameter()
expected = 5
self.assertEqual(
actual, expected,
'should return the path with ' + 'the max number of vertices')
def test_insert(self):
b = BST.build([])
actual = b.insert(3)
expected = [None, 3, None, None, 1]
self.assertEqual(actual, expected, 'should have inserted the '+
'correct single node into the BST')
actual = b.insert(1)
self.assertEqual(actual[PARENT][KEY], 3, 'should be a child of 3')
self.assertIsNone(actual[LEFT], 'should have no left child')
self.assertIsNone(actual[RIGHT], 'should have not right child')
self.assertEqual(actual[SIZE], 1, 'new node is a leaf')
self.assertEqual(b.root[SIZE], 2, 'root can access 2 nodes')
def test_insert(self):
b = BST.build([])
actual = b.insert(3)
expected = [None, 3, None, None, 1]
self.assertEqual(
actual, expected,
'should have inserted the ' + 'correct single node into the BST')
actual = b.insert(1)
self.assertEqual(actual[PARENT][KEY], 3, 'should be a child of 3')
self.assertIsNone(actual[LEFT], 'should have no left child')
self.assertIsNone(actual[RIGHT], 'should have not right child')
self.assertEqual(actual[SIZE], 1, 'new node is a leaf')
self.assertEqual(b.root[SIZE], 2, 'root can access 2 nodes')
def test_node_size_gets_modified_on_deletion(self):
b = BST.build([3,1,2,5,4])
self.assertEqual(b.search(3)[SIZE], 5, '3 has size 6')
b.delete(2) # Node is a leaf.
self.assertEqual(b.search(1)[SIZE], 1, '1 has no more children')
self.assertEqual(b.search(3)[SIZE], 4, 'root has 4 children now')
b.delete(5) # Node is in the middle.
self.assertEqual(b.search(4)[SIZE], 1, 'the size of 1 is unchanged')
self.assertEqual(b.search(3)[SIZE], 3, 'root has 3 children after del')
b.delete(3) # Node is the root.
self.assertEqual(b.search(4)[SIZE], 1, 'the size of 1 is unchanged')
self.assertEqual(b.search(1)[SIZE], 2, 'the new root is 1 and has size of 2')
def test_rotate_correctly_updates_sizes(self):
""" Makes sure the rotate operation updates node sizes accordingly.
(3) (3)
/ \ / \
(1) (5) (1) (7)
\ / \ => \ / \
(2) (4) (7) (2) (5) (8)
/ \ / \
(6) (8) (4) (6)
"""
b = BST.build([3,1,2,5,4,7,8,6])
b.rotate(b.search(5), RIGHT)
self.assertEqual(b.search(3)[SIZE], 8, 'root has the same size')
self.assertEqual(b.search(5)[SIZE], 3, 'rotated node has new size')
self.assertEqual(b.search(7)[SIZE], 5, 'rotated node has new size')
def test_rotate_correctly_updates_sizes(self):
""" Makes sure the rotate operation updates node sizes accordingly.
(3) (3)
/ \ / \
(1) (5) (1) (7)
\ / \ => \ / \
(2) (4) (7) (2) (5) (8)
/ \ / \
(6) (8) (4) (6)
"""
b = BST.build([3, 1, 2, 5, 4, 7, 8, 6])
b.rotate(b.search(5), RIGHT)
self.assertEqual(b.search(3)[SIZE], 8, 'root has the same size')
self.assertEqual(b.search(5)[SIZE], 3, 'rotated node has new size')
self.assertEqual(b.search(7)[SIZE], 5, 'rotated node has new size')
def test_node_size_gets_modified_on_deletion(self):
b = BST.build([3, 1, 2, 5, 4])
self.assertEqual(b.search(3)[SIZE], 5, '3 has size 6')
b.delete(2) # Node is a leaf.
self.assertEqual(b.search(1)[SIZE], 1, '1 has no more children')
self.assertEqual(b.search(3)[SIZE], 4, 'root has 4 children now')
b.delete(5) # Node is in the middle.
self.assertEqual(b.search(4)[SIZE], 1, 'the size of 1 is unchanged')
self.assertEqual(b.search(3)[SIZE], 3, 'root has 3 children after del')
b.delete(3) # Node is the root.
self.assertEqual(b.search(4)[SIZE], 1, 'the size of 1 is unchanged')
self.assertEqual(
b.search(1)[SIZE], 2, 'the new root is 1 and has size of 2')
def test_delete(self):
b = BST.build([3, 1, 2, 5, 4])
removed = b.delete(2) # Node is a leaf.
self.assertEqual(removed[KEY], 2, 'returns the removed node')
self.assertIsNone(b.search(2), 'should not find 2 anymore')
self.assertIsNone(b.search(1)[RIGHT], '1 has no more children')
removed = b.delete(5) # Node has only one child.
self.assertEqual(removed[KEY], 5, 'returns the removed node')
self.assertIsNone(b.search(5), 'should have removed 5')
self.assertEqual(b.search(4)[PARENT][KEY], 3, 'should have hoisted 4')
removed = b.delete(3) # Node has both children.
self.assertEqual(removed[KEY], 3, 'returns the removed node')
self.assertIsNone(b.search(3), 'should have removed 3')
self.assertEqual(b.root[KEY], 1, 'new root is 1')
def test_unballanced_graph_diameter(self):
""" Given the following binary search tree:
(1)
\
(2)
\
(3)
\
(4)
\
(5)
"""
tree = BST.build([1,2,3,4,5])
actual = tree.diameter()
expected = 5
self.assertEqual(actual, expected, 'should return the path with '+
'the max number of vertices')
def test_delete(self):
b = BST.build([3,1,2,5,4])
removed = b.delete(2) # Node is a leaf.
self.assertEqual(removed[KEY], 2, 'returns the removed node')
self.assertIsNone(b.search(2), 'should not find 2 anymore')
self.assertIsNone(b.search(1)[RIGHT], '1 has no more children')
removed = b.delete(5) # Node has only one child.
self.assertEqual(removed[KEY], 5, 'returns the removed node')
self.assertIsNone(b.search(5), 'should have removed 5')
self.assertEqual(b.search(4)[PARENT][KEY], 3, 'should have hoisted 4')
removed = b.delete(3) # Node has both children.
self.assertEqual(removed[KEY], 3, 'returns the removed node')
self.assertIsNone(b.search(3), 'should have removed 3')
self.assertEqual(b.root[KEY], 1, 'new root is 1')
def test_unballanced_graph_diameter(self):
""" Given the following binary search tree:
(1)
\
(2)
\
(3)
\
(4)
\
(5)
"""
tree = BST.build([1, 2, 3, 4, 5])
actual = tree.diameter()
expected = 5
self.assertEqual(
actual, expected,
'should return the path with ' + 'the max number of vertices')
def test_successor(self):
b = BST.build([3, 1, 2, 5, 4])
actual = b.successor(6)
self.assertIsNone(actual, 'did not find any node with key 6')
actual = b.successor(1)
self.assertEqual(actual[KEY], 2, 'successor of 1 is 2')
actual = b.successor(2)
self.assertEqual(actual[KEY], 3, 'successor of 2 is 3')
actual = b.successor(3)
self.assertEqual(actual[KEY], 4, 'successor of 3 is 4')
actual = b.successor(4)
self.assertEqual(actual[KEY], 5, 'successor of 4 is 5')
actual = b.successor(5)
self.assertIsNone(actual, '5 is max of tree so no successor')
def test_predecessor(self):
b = BST.build([3, 1, 2, 5, 4])
actual = b.predecessor(6)
self.assertIsNone(actual, 'did not find any node with key 6')
actual = b.predecessor(1)
self.assertIsNone(actual, '1 is min, so no predecessor')
actual = b.predecessor(2)
self.assertEqual(actual[KEY], 1, 'predecessor of 2 is 1')
actual = b.predecessor(3)
self.assertEqual(actual[KEY], 2, 'predecessor of 3 is 2')
actual = b.predecessor(4)
self.assertEqual(actual[KEY], 3, 'predecessor of 4 is 3')
actual = b.predecessor(5)
self.assertEqual(actual[KEY], 4, 'predecessor of 4 is 3')
def test_successor(self):
b = BST.build([3,1,2,5,4])
actual = b.successor(6)
self.assertIsNone(actual, 'did not find any node with key 6')
actual = b.successor(1)
self.assertEqual(actual[KEY], 2, 'successor of 1 is 2')
actual = b.successor(2)
self.assertEqual(actual[KEY], 3, 'successor of 2 is 3')
actual = b.successor(3)
self.assertEqual(actual[KEY], 4, 'successor of 3 is 4')
actual = b.successor(4)
self.assertEqual(actual[KEY], 5, 'successor of 4 is 5')
actual = b.successor(5)
self.assertIsNone(actual, '5 is max of tree so no successor')
def test_predecessor(self):
b = BST.build([3,1,2,5,4])
actual = b.predecessor(6)
self.assertIsNone(actual, 'did not find any node with key 6')
actual = b.predecessor(1)
self.assertIsNone(actual, '1 is min, so no predecessor')
actual = b.predecessor(2)
self.assertEqual(actual[KEY], 1, 'predecessor of 2 is 1')
actual = b.predecessor(3)
self.assertEqual(actual[KEY], 2, 'predecessor of 3 is 2')
actual = b.predecessor(4)
self.assertEqual(actual[KEY], 3, 'predecessor of 4 is 3')
actual = b.predecessor(5)
self.assertEqual(actual[KEY], 4, 'predecessor of 4 is 3')
def test_is_ballanced_binary_search_tree(self):
""" Test three cases:
(3) (3) (3)
/ \ / \
(1) (7) (1) (7)
\ / \ / \
(2) (5) (10) (5) (10)
/ \
(4) (6)
"""
bst1 = BST.build([3])
bst2 = BST.build([3, 1, 2, 7, 5, 4, 6, 10])
bst3 = BST.build([3, 1, 7, 5, 10])
self.assertTrue(BST.is_ballanced_binary_search_tree(bst1))
self.assertFalse(BST.is_ballanced_binary_search_tree(bst2))
self.assertTrue(BST.is_ballanced_binary_search_tree(bst3))
def test_is_ballanced_binary_search_tree(self):
""" Test three cases:
(3) (3) (3)
/ \ / \
(1) (7) (1) (7)
\ / \ / \
(2) (5) (10) (5) (10)
/ \
(4) (6)
"""
bst1 = BST.build([3])
bst2 = BST.build([3, 1, 2, 7, 5, 4, 6, 10])
bst3 = BST.build([3, 1, 7, 5, 10])
self.assertTrue(BST.is_ballanced_binary_search_tree(bst1))
self.assertFalse(BST.is_ballanced_binary_search_tree(bst2))
self.assertTrue(BST.is_ballanced_binary_search_tree(bst3))
def search_and_splay(self, key):
""" After a successful search operation the returned node is hoisted
to the root before being returned.
"""
node = BST.search(self, key)
return self.splay(node)
def test_range_query(self):
b = BST.build([3,1,2,5,4])
actual = b.range_query(2, 4)
expected = [2,3,4]
self.assertEqual(actual, expected, 'should return a range of data')
def insert(self, key):
""" After regular BST insert, the new node is hoisted to the root. """
node = BST.insert(self, key)
return self.splay(node)
def test_range_query(self):
b = BST.build([3, 1, 2, 5, 4])
actual = b.range_query(2, 4)
expected = [2, 3, 4]
self.assertEqual(actual, expected, 'should return a range of data')
def test_min(self):
b = BST.build([3,1,2,5,4])
self.assertEqual(b.get_min()[KEY], 1, 'should find the min value')
def test_output(self):
b = BST.build([3,1,2,5,4])
actual = b.list_sorted()
expected = [1,2,3,4,5]
self.assertEqual(actual, expected, 'should list the key in order')
