Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Find if given vertical level of binary tree is sorted or not in Python
Suppose we have binary tree; we have to check whether the given vertical level of the binary tree is sorted or not. When two nodes are overlapping, check they are in sorted sequence in the level they belong.
So, if the input is like l = -1
then the output will be True, as elements in level -1 are 3,7 and they are sorted.
To solve this, we will follow these steps −
if root is null, then
return True
previous_value := -inf
current_level := 0
current_node := a new tree node with value 0
Define one dequeue named q
insert (root, 0) at the end of q
while q is not empty, do
current_node := q[0, 0]
current_level := q[0, 1]
delete element from left of q
if current_level is same as level, then
if previous_value <= current_node.val, then
previous_value := current_node.val
otherwise,
return False
if current_node.left is not-null, then
insert (current_node.left, current_level - 1) at the end of q
if current_node.right is non-null, then
insert (current_node.right, current_level + 1) at the end of q
return True
Example
Let us see the following implementation to get better understanding −
from collections import deque from sys import maxsize INT_MIN = -maxsize class TreeNode: def __init__(self, key): self.val = key self.left = None self.right = None def are_elements_sorted(root, level): if root is None: return True previous_value = INT_MIN current_level = 0 current_node = TreeNode(0) q = deque() q.append((root, 0)) while q: current_node = q[0][0] current_level = q[0][1] q.popleft() if current_level == level: if previous_value <= current_node.val: previous_value = current_node.val else: return False if current_node.left: q.append((current_node.left, current_level - 1)) if current_node.right: q.append((current_node.right, current_level + 1)) return True root = TreeNode(2) root.left = TreeNode(3) root.right = TreeNode(6) root.left.left = TreeNode(8) root.left.right = TreeNode(5) root.left.right.left = TreeNode(7) level = -1 print(are_elements_sorted(root, level))
Input
root = TreeNode(2) root.left = TreeNode(3) root.right = TreeNode(6) root.left.left = TreeNode(8) root.left.right = TreeNode(5) root.left.right.left = TreeNode(7)
Output
True
28 Views
