def build_from_PostIn(postorder, inorder):
if inorder and postorder:
index = inorder.index(postorder.pop())
root = Node(inorder[index])
root.right = build_from_PostIn(postorder, inorder[index + 1:])
root.left = build_from_PostIn(postorder, inorder[:index])
return root
def _create_min_bst(self, array, start, end):
if end < start:
return None
mid = (start + end) // 2
node = Node(array[mid])
node.left = self._create_min_bst(array, start, mid - 1)
node.right = self._create_min_bst(array, mid + 1, end)
return node
def build_from_PreIn(preorder, inorder):
if inorder and preorder:
index = inorder.index(preorder[0])
root = Node(inorder[index])
root.left = build_from_PreIn(preorder[1:index + 1], inorder[:index])
root.right = build_from_PreIn(preorder[index + 1:],
inorder[index + 1:])
return root
def test_get():
root = Node('b', 5)
root.left = Node('a', 3)
root.right = Node('c', 2)
bst = BST(root)
assert bst.get('a') == 3
assert bst.get('c') == 2
assert bst.get('d') is None
def print_Trees(first, last):
trees = []
for i in range(first, last + 1):
for j in print_Trees(first, i - 1):
for y in print_Trees(i + 1, last):
# print("hi")
BT = Binary_Tree()
root = Node(i)
root.left = j
root.right = y
BT.root = root
trees.append(root)
return trees or [None]
from BST import Node def inorder(root,arr): if root: inorder(root.left,arr) arr.append(root.key) inorder(root.right,arr) def isBST(root): arr = [] inorder(root,arr) return arr == sorted(arr) root = Node(6) root.left = Node(9) root.right = Node(10) root.left.left = Node(17) root.left.right = Node(4) root.right.right = Node(11) print isBST(root) root = Node(6) root.left = Node(4) root.right = Node(7) print isBST(root)
from BST import Node
def inorder(root, arr):
if root:
inorder(root.left, arr)
arr.append(root.key)
inorder(root.right, arr)
def isBST(root):
arr = []
inorder(root, arr)
return arr == sorted(arr)
root = Node(6)
root.left = Node(9)
root.right = Node(10)
root.left.left = Node(17)
root.left.right = Node(4)
root.right.right = Node(11)
print isBST(root)
root = Node(6)
root.left = Node(4)
root.right = Node(7)
print isBST(root)
root = new_node
else:
if node.key > root.key:
if root.right is None:
root.right = node
else:
Insert_rec(root.right, node)
else:
if root.left is None:
root.left = node
else:
Insert_rec(root.left, node)
root = Node(20)
root.left = Node(8)
root.right = Node(22)
root.left.left = Node(4)
root.left.right = Node(12)
root.left.right.left = Node(10)
root.left.right.right = Node(14)
n1 = 10
n2 = 14
t = lca(root, n1, n2)
print "LCA of %d and %d is %d" % (n1, n2, t.key)
n1 = 14
n2 = 8
t = lca(root, n1, n2)
print "LCA of %d and %d is %d" % (n1, n2, t.key)
tree = BST()
tree.add(1)
tree.add(0)
tree.remove(1)
assert tree.root.key == 0
tree.remove(0)
assert tree.root is None
#################################
## Validate BST
#################################
n1 = Node(1)
root = Node(2)
root.left = n1
def is_bst(root):
if root is None:
return True
if root.left and root.left.key > root.key:
return False
if root.right and root.right.key < root.key:
return False
return is_bst(root.left) and is_bst(root.right)
assert is_bst(root) == True
fake_tree = Node(0, right=n1)
n1.left = root
from BST import Node
def max_sum(root):
if root is None:
return 0
l = max_sum(root.left)
r = max_sum(root.right)
max_single = max(max(l, r) + root.key, root.key)
max_top = max(max_single, l + r + root.key)
max_sum.res = max(max_sum.res, max_top)
return max_single
def max_util(root):
max_sum.res = float("-inf")
max_sum(root)
return max_sum.res
root = Node(10)
root.left = Node(2)
root.right = Node(10)
root.left.left = Node(20)
root.left.right = Node(1)
root.right.right = Node(-25)
root.right.right.left = Node(3)
root.right.right.right = Node(4)
print max_util(root)
if not root: root = new_node else: if node.key > root.key: if root.right is None: root.right = node else: Insert_rec(root.right,node) else: if root.left is None: root.left = node else: Insert_rec(root.left,node) root = Node(20) root.left = Node(8) root.right = Node(22) root.left.left = Node(4) root.left.right = Node(12) root.left.right.left = Node(10) root.left.right.right = Node(14) n1 = 10 ; n2 = 14 t = lca(root, n1, n2) print "LCA of %d and %d is %d" %(n1, n2, t.key) n1 = 14 ; n2 = 8 t = lca(root, n1, n2) print "LCA of %d and %d is %d" %(n1, n2 , t.key) n1 = 10 ; n2 = 22
from BST import Node
def max_sum(root):
if root is None:
return 0
l = max_sum(root.left)
r = max_sum(root.right)
max_single = max(max(l,r)+root.key,root.key)
max_top = max(max_single,l+r+root.key)
max_sum.res = max(max_sum.res,max_top)
return max_single
def max_util(root):
max_sum.res = float("-inf")
max_sum(root)
return max_sum.res
root = Node(10)
root.left = Node(2)
root.right = Node(10)
root.left.left = Node(20)
root.left.right = Node(1)
root.right.right = Node(-25)
root.right.right.left = Node(3)
root.right.right.right = Node(4)
print max_util(root)
from BST import Node
def validate_tree(root):
if not root or (not root.left and not root.right):
return True
#for an imbalanced tree, there has to be cond to check if one of the childs is none
if (root.left and root.right and root.left.value < root.value
and root.right.value > root.value) or (
root.left.value < root.value
and not root.right) or (root.right.value > root.value
and not root.left):
return validate_tree(root.left) and validate_tree(root.right)
return False
n = Node(2)
n.left = Node(1)
n.left.left = Node(0)
n.right = Node(3)
print(validate_tree(n))