def _compose_ht_tree(self, text): """Huffman tree construction for text.""" freq_table = self._compute_chr_freq(text) ht_queue = HeapPriorityQueue() for freq, lett in freq_table: ht_tree = LinkedBinaryTree() ht_tree._add_root((freq, lett)) ht_queue.add(freq, ht_tree) while len(ht_queue) > 1: (freq1, subtree1) = ht_queue.remove_min() (freq2, subtree2) = ht_queue.remove_min() freq = freq1 + freq2 ht_tree = LinkedBinaryTree() ht_tree._add_root((freq, None)) ht_tree._attach(ht_tree.root(), subtree1, subtree2) ht_queue.add(freq, ht_tree) _, ht_tree = ht_queue.remove_min() return ht_tree
if T.left(p) is not None: inorder(T.left(p)) print T._validate(p)._element if T.right(p) is not None: inorder(T.right(p)) if __name__ == '__main__': import random def build_tree(T, p, level): if level > 5: return None else: if T.left(p) is None: T._add_left(p, random.randint(1, 10)) build_tree(T, T.left(p), level+1) if T.right(p) is None: T._add_right(p, random.randint(1, 10)) build_tree(T, T.right(p), level+1) test_tree = LinkedBinaryTree() test_tree._add_root('10') build_tree(test_tree, test_tree.root(), 1) count = 1 for x in test_tree.positions(): print str(count) +': ' + str(test_tree._validate(x)._element) count += 1
"""Preorder traversal""" # 应该使用普通的树而不是二叉树 from linked_binary_tree import LinkedBinaryTree # Electronics R’Us # 1 R&D # 2 Sales # 2.1 Domestic # 2.2 International # 2.2.1 Canada # 2.2.2 America toc = LinkedBinaryTree() toc._add_root('Electronics R’Us') toc._add_left(toc.root(), 'R&D') toc._add_right(toc.root(), 'Sales') toc._add_left(toc.right(toc.root()), 'Domestic') toc._add_right(toc.right(toc.root()), 'International') toc._add_left(toc.right(toc.right(toc.root())), 'Canada') toc._add_right(toc.right(toc.right(toc.root())), 'America') def parenthesize(t, p, rep): if t.is_empty(): return rep += str(p.element()) if not t.is_leaf(p): first_time = True for c in t.children(p):
from linked_binary_tree import LinkedBinaryTree a = LinkedBinaryTree() print('!!!') a._add_root('!!') a._add_left(a.root(), '????') print('!') print(a.left(a.root()).element()) a._delete(a.left(a.root()))
def test_root(self): blank_tree = LinkedBinaryTree() root = blank_tree.root() self.assertEqual(root, None) # Should return None for an empty tree. root = self.tree.root() self.assertEqual(root.element(), "Root")
class TestSimpleCases(unittest.TestCase): """ Test obvious cases to confirm basic functionality and syntax correctness. """ def setUp(self): self.tree = LinkedBinaryTree() # Create a proper balanced tree with 3 levels (8 elements) self.root = self.tree._add_root("Root") self.left = self.tree._add_left(self.root, "L2 left child") self.right = self.tree._add_right(self.root, "L2 right child") self.lev3_first_left = self.tree._add_left(self.left, "L3 left-1") self.tree._add_right(self.left, "L3 right-1") self.tree._add_left(self.right, "L3 left-2") self.tree._add_right(self.right, "L3 right-2") def test_validate(self): # Passing an object of type other than Position should raise TypeError with self.assertRaises(TypeError): self.tree._validate("spam") # Wrong container should raise value error position_from_other_container = LinkedBinaryTree()._add_root( "spam root") with self.assertRaises(ValueError): self.tree._validate(position_from_other_container) # If node was deprecated, meaning it was set to be its own parent per # the internal convention for deprecated nodes, then should raise # value error. p = self.lev3_first_left p._node._parent = p._node with self.assertRaises(ValueError): self.tree._validate(p) # ---------------------------------- public methods -------------------- def test_root(self): blank_tree = LinkedBinaryTree() root = blank_tree.root() self.assertEqual(root, None) # Should return None for an empty tree. root = self.tree.root() self.assertEqual(root.element(), "Root") def test_parent(self): # should return None when called on p = root parent_of_root = self.tree.parent(self.tree.root()) self.assertEqual(parent_of_root, None) parent_of_left = self.tree.parent(self.left) # Position object from # setUp, name self.left references # root's left child. self.assertEqual(parent_of_left, self.root) # Try the next level down parent_of_node = self.tree.parent(self.lev3_first_left) self.assertEqual(parent_of_node, self.left) def test_left(self): left = self.tree.left(self.root) # parent's left should be the object # stored as self.left self.assertEqual(left, self.left) def test_right(self): right = self.tree.right(self.root) # root's right should be the object # stored as self.right self.assertEqual(right, self.right) def test_num_children(self): self.assertEqual(self.tree.num_children(self.root), 2) # Root has 2 children self.assertEqual(self.tree.num_children(self.right), 2) # Right has 2 self.assertEqual(self.tree.num_children(self.lev3_first_left), 0) # This node should be in the # bottom level of the setUp # tree and therefore have # no children. # ------------------- tests for concrete methods inherited from Tree ------ def test_is_root(self): """Concrete method implemented in the Tree abstract base class and inherited through to LBT class.""" # Should be true for root self.assertTrue(self.tree.is_root(self.root)) # Should be false for a node from the middle or bottom layer self.assertFalse(self.tree.is_root(self.right)) self.assertFalse(self.tree.is_root(self.lev3_first_left)) def test_is_leaf(self): # testing _attach will "coverage" this pass def test_is_empty(self): # testing _attach will "coverage this pass def test_height(self): """ Test the height method defined in the Tree abstract base class that LBT class has through inheritance. """ # Calling it on root should return 2, the height of the full three-level # tree. self.assertEqual(self.tree.height(self.root), 2) # Height of a node in the middle layer should be 1 self.assertEqual(self.tree.height(self.right), 1) # Height of a node in the bottom layer should be 0 self.assertEqual(self.tree.height(self.lev3_first_left), 0) def test_depth(self): """ Test the depth method defined in the Tree abstract base class and inherited in the LBT class. """ # Depth of a node in the bottom later should be 2 (2 levels separating # that Position from root Position). self.assertEqual(self.tree.depth(self.lev3_first_left), 2) # Depth of node in middle layer should be 1 self.assertEqual(self.tree.depth(self.left), 1) # Depth of root should be zero self.assertEqual(self.tree.depth(self.root), 0) def test_attach(self): """Tests for the nonpublic _attach method, mainly to hit inherited public methods that it will call.""" new_tree = LinkedBinaryTree() ntroot = new_tree._add_root("New tree root") new_tree._add_left(ntroot, "NT left") new_tree._add_right(ntroot, "NT right") new_tree2 = LinkedBinaryTree() nt2root = new_tree2._add_root("2nd new tree root") new_tree2._add_left(nt2root, "left") new_tree2._add_right(nt2root, "right") self.tree._attach(self.lev3_first_left, new_tree, new_tree2) # For now just pass if none of these calls raised an error, no # unittest.assertSomething method call def test_positions(self): # This covers postorder() method for purposes # of the "coverage" metric. for position in self.tree.positions( ): # Test that they can be iterated self.assertIsInstance(position, LinkedBinaryTree.Position) # and that # they're all Positions ## def test_preorder(self): # placeholder ## pass def test_postorder(self): for position in self.tree.postorder(): self.assertIsInstance(position, LinkedBinaryTree.Position)
"""Preorder traversal""" # 应该使用普通的树而不是二叉树 from linked_binary_tree import LinkedBinaryTree # Electronics R’Us # 1 R&D # 2 Sales # 2.1 Domestic # 2.2 International # 2.2.1 Canada # 2.2.2 America toc = LinkedBinaryTree() toc._add_root('Electronics R’Us') toc._add_left(toc.root(), 'R&D') toc._add_right(toc.root(), 'Sales') toc._add_left(toc.right(toc.root()), 'Domestic') toc._add_right(toc.right(toc.root()), 'International') toc._add_left(toc.right(toc.right(toc.root())), 'Canada') toc._add_right(toc.right(toc.right(toc.root())), 'America') # Solution 1: O(n^2) # for p in toc.preorder(): # print(toc.depth(p)*2*' '+p.element()) # Solution 2: O(n) def preorder_indent(t, p, d): print(2 * d * ' ' + p.element()) for c in t.children(p): preorder_indent(t, c, d + 1)
from linked_binary_tree import LinkedBinaryTree # Construct Tree: T = LinkedBinaryTree() T.add_root(1) p1 = T.add_left(T.root(), 2) p2 = T.add_right(T.root(), 3) T.add_left(p1, 4) T.add_right(p1, 5) p3 = T.add_left(p2, 6) p4 = T.add_right(p2, 7) T.add_left(p3, 8) T.add_right(p3, 9) T.add_right(p4, 10) # Check Traversals: print("\nPreorder: ") for p in T.preorder(): print(p.element()) print("\nPostorder: ") for p in T.postorder(): print(p.element()) print("\nInorder: ")