ssshukla26

# Leetcode : 449
# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Codec:
    def serialize(self, root: Optional[TreeNode]) -> str:

ssshukla26

from typing import List, Optional

# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right

def inorder_traversal(root: Optional['TreeNode']) -> List[int]:
    # holds the inorder result

ssshukla26

# Leetcode 210:  Kahn's Algorithm
# https://www.youtube.com/watch?v=cIBFEhD77b4

from collections import defaultdict, deque
from typing import List, Tuple

def kahn_toposort(n: int, edges: List[Tuple[int, int]]) -> List[int]:
    # create adjacency graph as a dictionary where each node maps to its neighbors
    graph = defaultdict(list)
    # indegree list using list comprehension, initially all 0

ssshukla26

# Leetcode 48 : Rotate Image

class Solution:
    def rotate90(self, matrix: List[List[int]], offset: Tuple[int, int], n: int):
        if n > 1:
            # get offset
            x, y = offset

            # rotate edges : top << left << bottom << right
            top_i, top_j = x, y

ssshukla26

# Leetcode: 114. Flatten Binary Tree to Linked List

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:

ssshukla26

# Leetcode 25
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def reverseList(self, head: ListNode):
        prev = None
        curr = head

ssshukla26

    # Leetcode 61: Reorder List
    
    # function to find mid of a list 
    def findMidofList(self, head: ListNode) -> ListNode:
        slow, fast = head, head
        while fast and fast.next:
            slow = slow.next
            fast = fast.next.next
        return slow

ssshukla26

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Codec:

    def serialize(self, root):

ssshukla26

# Function to find prime factors of a number
def primeFactors(num):

    # Function to reduce num by a factor
    def reduceByFactor(factor):
        nonlocal num
        while num % factor == 0:
            num = num // factor
        return

ssshukla26

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    
    def deleteAndReplaceWithMin(self, root: TreeNode):