def test_tree_maker():
'''
1
/ \
2 3
/ \
4 5
'''
btree = BinaryTree.fromList([1, 2, 3, 4, None, None, 5])
assert btree is not None
assert btree.root is not None
assert btree.root.value == 1
assert btree.root.left.value == 2
assert btree.root.right.value == 3
assert btree.root.left.left.value == 4
assert btree.root.left.right == None
assert btree.root.right.left == None
assert btree.root.right.right.value == 5
assert btree.root.left.left.left == None
assert btree.root.left.left.right == None
assert btree.root.right.right.left == None
assert btree.root.right.right.right == None
'''
1
/ \
2 3
/ \ / \
4 5 6 7
In-order traversal: [4,2,5,1,6,3,7]
Pre-order traversal: [1,2,4,5,3,6,7]
Post-order traversal: [4,5,2,6,7,3,1]
'''
btree = BinaryTree.from_traversal([4,2,5,1,6,3,7], [1,2,4,5,3,6,7])
assert btree is not None
assert btree.root is not None
# Compare inorder and preorder traversals of the resulting tree
inorder, preorder = [], []
aggregate_list = lambda kwargs, data : kwargs['lst'].append(data)
btree.preorder_traversal(aggregate_list, lst=preorder)
btree.inorder_traversal(aggregate_list, lst=inorder)
assert inorder == [4,2,5,1,6,3,7]
assert preorder == [1,2,4,5,3,6,7]
btree = BinaryTree.from_traversal([4,2,5,1,6,3,7], postorder=[4,5,2,6,7,3,1])
assert btree is not None
assert btree.root is not None
# Compare inorder and postorder traversals of the resulting tree
inorder, postorder = [], []
aggregate_list = lambda kwargs, data : kwargs['lst'].append(data)
btree.postorder_traversal(aggregate_list, lst=postorder)
btree.inorder_traversal(aggregate_list, lst=inorder)
assert inorder ==[4,2,5,1,6,3,7]
assert postorder == [4,5,2,6,7,3,1]
def from_traversal_in_post(inorder, postorder):
# some checks to see if the inputs are in order (heh!)
if not inorder or not postorder:
return None
if len(inorder) != len(postorder):
return None
# helper function to recursively build the binary tree
# NOTE: Assumes no duplicates FIXME
def _from_traversal(inorder, postorder):
# Empty traversal lists, return empty node
if not inorder:
return None
# Create root node for this subtree
root = Node(postorder[-1])
# Locate root in inorder traversal sequence
root_idx = inorder.index(postorder[-1])
root.left = _from_traversal(inorder[:root_idx],
postorder[:root_idx])
root.right = _from_traversal(inorder[root_idx + 1:],
postorder[root_idx:-1])
return root
# call the helper function
root = _from_traversal(inorder, postorder)
return BinaryTree(root)
def populated_tree_2():
n1 = Node(42)
n2 = Node(100)
n3 = Node(600)
n4 = Node(15)
n5 = Node(160)
n6 = Node(200)
n7 = Node(350)
n8 = Node(125)
n9 = Node(175)
n10 = Node(4)
n11 = Node(500)
n1.left = n2
n1.right = n3
n2.left = n4
n2.right = n5
n3.left = n6
n3.right = n7
n5.left = n8
n5.right = n9
n7.left = n10
n7.right = n11
bt = BinaryTree(n1)
return bt
def test_zigzag_traversal():
'''
1
/ \
2 3
/ \
4 5
'''
btree = BinaryTree.fromList([1, 2, 3, 4, None, None, 5])
assert btree is not None
assert btree.root is not None
collate_fn = lambda kwargs, data: kwargs['lst'].append(data)
l = []
btree.zigzag_levelorder_traversal(collate_fn, lst=l)
assert (l == [1, 3, 2, 4, 5])
'''
1
/ \
2 3
/ \ / \
4 5 6 7
'''
btree = BinaryTree.fromList([1, 2, 3, 4, 5, 6, 7])
assert btree is not None
assert btree.root is not None
l = []
btree.zigzag_levelorder_traversal(collate_fn, lst=l)
assert (l == [1, 3, 2, 4, 5, 6, 7])
'''
a
/ \
b c
/ \ / \
d e f g
/ \
h i
'''
btree = BinaryTree.fromList("abcdefghi")
assert btree is not None
assert btree.root is not None
l = []
btree.zigzag_levelorder_traversal(collate_fn, lst=l)
assert (''.join(l) == "acbdefgih")
def clone_r(bintree):
def _clone(root):
if not root:
return None
root_ = Node(root.value)
root_.left = _clone(root.left)
root_.right = _clone(root.right)
return root_
if not bintree or not bintree.root:
return None
return BinaryTree(root=_clone(bintree.root))
def clone_i(bintree):
s = Stack()
# contains cloned node references, a', for each node a
# doubles as visited[] map => if cloned_nodes[a] is not empty => a is visited
cloned_nodes = {}
if not bintree or not bintree.root:
return None
# Helper function to check if a node is already 'done'/processed
# a node is considered 'done'
# if its value is None
# or
# if it has already been cloned.
isDone = lambda node, cloned_node: True if (node is None or cloned_node
is not None) else False
s.push(bintree.root)
while s:
node = s.top()
left_clone = cloned_nodes.get(node.left)
right_clone = cloned_nodes.get(node.right)
# Both left and right subtrees are done
# pop 'node' off the stack, create a clone, and map the clone to the original
# Link cloned node's left and right children
if isDone(node.left, left_clone) and isDone(
node.right, right_clone):
s.pop()
node_ = Node(node.value)
node_.left = left_clone
node_.right = right_clone
cloned_nodes[node] = node_
else:
# push both left and right children to the stack
# NOTE: This actually processes reverse post-order (right-left-root)
# unless we push right, followed by left onto the stack
# but order shouldnt really matter
s.push(node.left) if node.left else None
s.push(node.right) if node.right else None
return BinaryTree(root=cloned_nodes[bintree.root])
def fromList(array):
# lambda helper functions to get parent, left, and right nodes indices
# from current index
parent = lambda i: (i - 1) / 2
left = lambda i: 2 * i + 1
right = lambda i: 2 * i + 2
# All odd indices are left children,
# even indices are right children in the binary tree
isLeftChild = lambda i: (i & 1 == 1)
# root cannot be empty
if not array or array[0] is None:
return None
root = Node(array[0])
btree = BinaryTree(root)
nodes_list = [root]
for i in xrange(1, len(array)):
n = None
if array[i] is not None:
n = Node(array[i])
p = nodes_list[parent(i)]
if p is None:
continue
if isLeftChild(i):
p.left = n
else:
p.right = n
nodes_list.append(n)
return btree
def empty_tree_1():
return BinaryTree()
def traversals():
# prefix equation tree : "+a*bc"
'''
+
/ \
a *
/ \
b c
'''
root = Node("+")
lnode = Node("a")
rnode = Node("*")
root.setChildren(lnode, rnode)
rlnode = Node("b")
rrnode = Node("c")
rnode.setChildren(rlnode, rrnode)
btree = BinaryTree(root)
print 'Preorder: ',
btree.preorder_traversal()
print
l = []
# define a lambda function that collates individual node values into a list
collate_fn = lambda kwargs, data : kwargs['lst'].append(data)
btree.preorder_traversal(collate_fn, lst=l)
assert (l == ['+', 'a', '*', 'b', 'c'])
print 'Postorder: ',
btree.postorder_traversal()
print
l = []
btree.postorder_traversal(collate_fn, lst=l)
assert (l == ['a', 'b', 'c', '*', '+'])
print 'Inorder: ',
btree.inorder_traversal()
print
l = []
btree.inorder_traversal(collate_fn, lst=l)
assert (l == ['a', '+', 'b', '*', 'c'])
print 'Level order: ',
btree.levelorder_traversal()
print
l = []
btree.levelorder_traversal(collate_fn, lst=l)
assert (l == ['+', 'a', '*', 'b', 'c'])
print 'Left View: ',
btree.left_view()
print
l = []
btree.left_view(collate_fn, lst=l)
assert (l == ['+', 'a', 'b'])
print 'Right View: ',
btree.right_view()
print
l = []
btree.right_view(collate_fn, lst=l)
assert (l == ['+', '*', 'c'])
print 'Top View: ',
btree.top_view()
print
l = []
btree.top_view(collate_fn, lst=l)
assert (l == ['+', 'a', '*', 'c'])
print 'Top View L-R: ',
btree.top_view_LR()
print
l = []
btree.top_view_LR(collate_fn, lst=l)
assert (l == ['a', '+', '*', 'c'])
print 'Bottom View: ',
btree.bottom_view()
print
l = []
btree.bottom_view(collate_fn, lst=l)
assert (l == ['a', 'b', '*', 'c'])
print 'Testcase TC1 passed!'
def basic_tests():
# prefix equation tree : "+a*bc"
'''
+
/ \
a *
/ \
b c
'''
root = Node("+")
lnode = Node("a")
rnode = Node("*")
root.setChildren(lnode, rnode)
rlnode = Node("b")
rrnode = Node("c")
rnode.setChildren(rlnode, rrnode)
btree = BinaryTree(root)
assert(btree.height() == 3)
assert btree.span() == 3
assert btree.width() == 2
'''
1
/ \
3 2
/ \ \
5 3 9
'''
root = Node("1")
root.setChildren(Node("3"), Node("2"))
root.left.setChildren(Node("5"), Node("3"))
root.right.right = Node("9")
btree2 = BinaryTree(root)
assert(btree2.height() == 3)
assert btree2.span() == 4
assert btree2.width() == 3
'''
1
/ \
3 2
/
5
'''
root = Node("1")
root.setChildren(Node("3"), Node("2"))
root.left.left = Node("5")
btree3 = BinaryTree(root)
assert(btree3.height() == 3)
assert btree3.span() == 3
assert btree3.width() == 2
btree4 = BinaryTree(Node('blah'))
assert(btree4.height() == 1)
assert btree4.span() == 0
assert btree4.width() == 1
def test_path_and_lca(): ''' 1 / \ 2 3 / \ / \ 4 5 6 7 ''' root = Node(1) lnode = Node(2) rnode = Node(3) root.setChildren(lnode, rnode) lnode.setChildren(Node(4), Node(5)) rnode.setChildren(Node(6), Node(7)) btree = BinaryTree(root) assert(btree.height() == 3) nodes = btree.path_n(7) path = [1,3,7] i=0 assert(len(nodes) == 3) for n in nodes: assert n.value == path[i] i += 1 # find path using a node reference nodes = btree.path_n(rnode) path = [1,3] i=0 for n in nodes: assert n.value == path[i] i += 1 assert(btree.path_n(8) == []) assert btree.path_1(7) == [1,3,7] assert btree.path_1(5) == [1,2,5] assert btree.path_1(6) == [1,3,6] assert btree.path_1(1) == [1] assert btree.path_1(2) == [1, 2] assert btree.path_1(9) == [] assert btree.path_2(7) == [1,3,7] assert btree.path_2(5) == [1,2,5] assert btree.path_2(6) == [1,3,6] assert btree.path_2(1) == [1] assert btree.path_2(2) == [1, 2] assert btree.path_2(9) == [] assert btree.path(2) == [1, 2] assert btree.path(9) == [] # Test paths-based LCA n1 = rnode.left n2 = lnode.right assert n1.value == 6 assert n2.value == 5 assert btree.lca_p(n1, n2) == root assert btree.lca_p(rnode, lnode) == root assert btree.lca_p(rnode.right, rnode.left) == rnode assert btree.lca_p(lnode.right, lnode.left) == lnode assert btree.lca_p(lnode.left, rnode.right) == root assert btree.lca_p(rnode, 2) == root assert btree.lca_p(7, rnode.left) == rnode assert btree.lca_p(5, 4) == lnode assert btree.lca_p(4, 7) == root assert btree.lca_p(2, 4) == root.left assert btree.lca_p(4, 2) == root.left assert btree.lca_p(3, 7) == root.right assert btree.lca_p(7, 3) == root.right # Test efficient LCA that obviates the need for storing paths assert btree.lca(n1, n2) == root assert btree.lca(rnode, lnode) == root assert btree.lca(rnode.right, rnode.left) == rnode assert btree.lca(lnode.right, lnode.left) == lnode assert btree.lca(lnode.left, rnode.right) == root assert btree.lca(rnode, 2) == root assert btree.lca(4, 5) == root.left assert btree.lca(5, 4) == root.left assert btree.lca(7, rnode.left) == rnode assert btree.lca(5, 4) == lnode assert btree.lca(4, 7) == root assert btree.lca(2, 4) == root.left assert btree.lca(4, 2) == root.left assert btree.lca(3, 7) == root.right assert btree.lca(7, 3) == root.right