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FirstCommonAncestor.py
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FirstCommonAncestor.py
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class Node:
def __init__(self, value, left=None, right=None, parent=None):
self.value = value
self.left = left
self.right = right
def __str__(self):
string = "{}:".format(self.value)
if self.left:
string = string + str(self.left.value) + ":"
else:
string = string + "0" + ":"
if self.right:
string = string + str(self.right.value) + ":"
else:
string = string + "0" + ":"
return string
class BinaryTree:
def __init__(self, tuples_lists):
self.nodes = {}
self.head = None
for node, left, right in tuples_lists:
root_node = self.nodes.get(node, Node(node))
self.nodes[node] = root_node
if left:
left_node = self.nodes.get(left, Node(left))
self.nodes[left] = left_node
root_node.left = left_node
if right:
right_node = self.nodes.get(right, Node(right))
self.nodes[right] = right_node
root_node.right = right_node
self.head = self.nodes.get(tuples_lists[0][0])
def find_path(self, node1, path1, node2, path2, node):
if node:
if node1 not in path1: path1.append(node)
if node2 not in path2: path2.append(node)
if node1 not in path1 or node2 not in path2:
self.find_path(node1, path1, node2, path2, node.left)
self.find_path(node1, path1, node2, path2, node.right)
if node1 not in path1: path1.remove(node)
if node2 not in path2: path2.remove(node)
def first_common_ancestor(self, node1, node2):
path1 = []
path2 = []
self.find_path(node1, path1, node2, path2, self.head)
smallpath = len(path1) if len(path1) < len(path2) else len(path2)
common_first_acestor = None
for i in range(smallpath):
if path1[i] == path2[i]:
common_first_acestor = path1[i]
return common_first_acestor
bt = BinaryTree([(10,5,15),(5,3,8),(15,13,17),(3,2,4),(8,7,0),(17,16,0)])
node = bt.first_common_ancestor(bt.nodes[5], bt.nodes[16])
print(node)