def test_eq_ne():
'''Test __eq__ and __ne__ of the BST class.'''
#Compare two basic, one-element trees.
tree_one = build_tree([1])
tree_two = build_tree([1])
assert tree_one == tree_two, \
'__eq__ did not work properly for one-element BST.'
assert not tree_one != tree_two, \
'__ne__ did not work properly for one-element BST.'
#Start with two identical tree, make changes to one, and check if the
#changes are detected.
tree_one = build_tree([2,1,3])
tree_two = build_tree([2,1,3])
assert tree_one == tree_two, \
'__eq__ did not work properly for three-element BST.'
tree_two.root.right.parent = 1
assert not tree_one == tree_two, \
'__eq__ did not detect different parent pointers between two BST.'
tree_two.root.right.parent = tree_two.root
assert tree_one == tree_two, \
'__eq__ did not work properly for three-element BST.'
bst.BST.insert(tree_two, 7)
assert not tree_one == tree_two, \
'__eq__ did not detect difference between two trees formed by \
adding a node to one of two identical trees.'
bst.BST.insert(tree_one, 7)
assert tree_one == tree_two, \
'__eq__ did not work properly.'
#Start with two different trees, change one so that it is identical to the
#other, and check if they are detected as equal
tree_one = build_tree([2,1,3])
tree_two = build_tree([1,2,3])
assert not tree_one == tree_two, \
'__eq__ did not work properly for three-element BST.'
bst.rotate_left(tree_two, tree_two.root)
assert tree_one == tree_two, \
'__eq__ did not work properly for three-element BST, or \
bst.rotate_left is broken.'
tree_three = build_tree([3,2,1])
bst.rotate_right(tree_three, tree_three.root)
assert tree_one == tree_three, \
'__eq__ did not work properly for three-element BST, or \
def test_rotate_left_rotate_right():
'''Test left and right rotation on non-root nodes of a tree.'''
tree_one = build_tree([5,4,6,1,2,7])
#Rotate left and right should not work on leaf nodes
bst.rotate_left(tree_one, tree_one.root.right.right)
assert tree_one == build_tree([5,4,6,1,2,7]), \
'bst.rotate_left inproperly rotated a tree at a leaf node.'
bst.rotate_right(tree_one, tree_one.root.right.right)
assert tree_one == build_tree([5,4,6,1,2,7]), \
'bst.rotate_right inproperly rotated a tree at a leaf node.'
#Test if rotate left and right work on random, non-root and non-leaf nodes.
bst.rotate_right(tree_one, tree_one.root.left)
assert tree_one == build_tree([5,1,4,2,6,7]), \
'bst.rotate_right did not work properly.'
bst.rotate_left(tree_one, tree_one.root.right)
assert tree_one == build_tree([5,1,4,2,7,6]), \
'bst.rotate_left did not work properly.'
bst.rotate_right(tree_one, tree_one.root.left.right)
assert tree_one == build_tree([5, 1, 2, 4, 7, 6]), \
'bst.rotate_right did not work properly.'
bst.rotate_left(tree_one, tree_one.root.left)
assert tree_one == build_tree([5, 2, 1, 4, 7, 6]), \
'bst.rotate_left did not work properly.'
def test_rotate_subtree_right(self):
'''Test left rotation on the root of a tree.'''
# A full binary search tree.
tree = build_tree([4, 2, 1, 3, 6, 5, 7])
old_tree = build_tree([4, 2, 1, 3, 6, 5, 7])
#tree.display()
#print ""
# The expected result.
target_tree = build_tree([4, 2, 1, 3, 5, 6, 7])
#target_tree.display()
assert tree.root.parent == None, 'tree.parent should have been None.'
assert bst.size(tree.root) == 7, 'tree size should be 7.'
assert bst.is_valid_tree(tree.root), \
'Valid tree was marked as invalid.'
bst.rotate_right(tree, tree.root.right)
#tree.display()
assert bst.size(tree.root) == 7, 'tree size should be 7.'
assert bst.is_valid_tree(tree.root), \
'Valid tree was marked as invalid.'
assert tree.root.right.data == old_tree.root.right.left.data, \
'''incorrect rotate, tree's new right substree should start
with 5'''
assert tree.root.data == old_tree.root.data, \
'''incorrect rotate, tree's root should not have changed'''
assert tree.root.right.right.right.data == \
old_tree.root.right.right.data, \
'''incorrect rotate, subtree's rightmost leaf should not have
changed'''
#RL is right.left, and LR is left.right
# This calls tree.__eq__(target_tree). Cool, huh? You need to write
# the __eq__ method in class BST to do the tree comparison.
assert tree == target_tree, '__eq__ did not work properly.'
# This calls tree.__ne__(target_tree).
assert not (tree != target_tree), '__ne__ did not work properly.'
def test_rotation(self):
Q = Tree_Node(1)
P = Tree_Node(2)
P.add_left(3)
P.add_right(4)
Q.left = P
Q.add_right(5)
first = []
postorder(Q, lambda x: first.append(str(x)))
second = []
Q = rotate_right(Q)
postorder(Q, lambda x: second.append(str(x)))
self.assertEqual("".join(first), "12345")
self.assertEqual("".join(second), "23145")
def process_user_command(game_tree, target_tree, curr, pic):
'''Read and process one command from the user, modifying BTNode game_tree
and current BTNode curr as appropriate and redrawing the new game_tree and
BTNode target_tree on Picture pic. Return the new value of curr.'''
d = {'Left': 'l', 'Right': 'r', 'Up': 'u', 'a': 'L', 's': 'R', 'q': 'q'}
cmd = d.get(KD.moving_by_keys().key, 'm')
# Only listen to valid commands.
if len(cmd) != 1 or cmd[0] not in 'qulrLR':
return curr
# Erase the old tree and redraw target_tree halfway across the window.
media.add_rect_filled(pic, 0, 0, WIDTH, HEIGHT, media.white)
draw(pic, target_tree.root, 0, WIDTH / 2, curr)
# Process user commands.
if cmd == 'q':
media.close(pic)
sys.exit(0)
elif cmd == 'u' and curr != None and curr.parent != None:
curr = curr.parent
elif cmd == 'l' and curr.left != None:
curr = curr.left
elif cmd == 'r' and curr.right != None:
curr = curr.right
elif cmd == 'L' and curr.right != None:
curr = bst.rotate_left(game_tree, curr)
elif cmd == 'R' and curr.left != None:
curr = bst.rotate_right(game_tree, curr)
# The parent attribute of the nodes of the new tree must be corrected.
# If curr is at the top, a rotation may have moved it there. Set the
# game_tree root to curr if that happened.
if curr.parent == None:
game_tree.root = curr
# Draw the new game tree.
draw(pic, game_tree.root, 0, 0, curr)
media.update(pic)
return curr
def fix_rbtree(node):
#assert !node.is_black
#case root
if is_root(node):
return
dad = node.parent
# case 0
if dad.is_black:
return
grandpa = node.parent.parent
if grandpa.is_nil: #dad is root
dad.flip_color
if dad == grandpa.left:
uncle = grandpa.red
else:
uncle = grandpa.left
#parent is red
#case 1
if uncle(node).is_red:
dad.flip_color()
uncle.flip_color()
grandparent.flip_color()
fix_rbtree(grandparent)
return
#case 2(uncle is black)
if dad == grandpa.right:
y = bst.rotate_left(grandpa)
node.flip_color()
fix_rbtree(y)
return
else:
y = bst.rotate_right(grandpa)
node.flip_color()
fix_rbtree(y)
return
def fix_rbtree(node):
#assert !node.is_black
#case root
if is_root(node):
return
dad = node.parent
# case 0
if dad.is_black:
return
grandpa = node.parent.parent
if grandpa.is_nil: #dad is root
dad.flip_color
if dad == grandpa.left:
uncle = grandpa.red
else:
uncle = grandpa.left
#parent is red
#case 1
if uncle(node).is_red:
dad.flip_color()
uncle.flip_color()
grandparent.flip_color()
fix_rbtree(grandparent)
return
#case 2(uncle is black)
if dad == grandpa.right:
y = bst.rotate_left(grandpa)
node.flip_color()
fix_rbtree(y)
return
else:
y = bst.rotate_right(grandpa)
node.flip_color()
fix_rbtree(y)
return
def process_user_command(game_tree, target_tree, curr, pic):
'''Read and process one command from the user, modifying BTNode game_tree
and current BTNode curr as appropriate and redrawing the new game_tree and
BTNode target_tree on Picture pic. Return the new value of curr.'''
cmd = raw_input(prompt)
# Only listen to valid commands.
while cmd not in 'shqulrLR':
cmd = raw_input(prompt)
# Erase the old tree and redraw target_tree halfway across the window.
media.add_rect_filled(pic, 0, 0, WIDTH, HEIGHT, media.white)
draw(pic, target_tree.root, 0, WIDTH / 2, curr)
# Process user commands.
if cmd == 'q':
media.close(pic)
return None
elif cmd == 'h':
solver.help_solve(game_tree, target_tree)
elif cmd== 's':
while game_tree != target_tree:
solver.help_solve(game_tree, target_tree)
elif cmd == 'u' and curr != None and curr.parent != None:
curr = curr.parent
elif cmd == 'l' and curr.left != None:
curr = curr.left
elif cmd == 'r' and curr.right != None:
curr = curr.right
elif cmd == 'L' and curr.right != None:
curr = bst.rotate_left(game_tree, curr)
elif cmd == 'R' and curr.left != None:
curr = bst.rotate_right(game_tree, curr)
# Draw the new game tree.
draw(pic, game_tree.root, 0, 0, curr)
media.update(pic)
return curr