Dhacker

[Dhacker @dhacker1_]

@AntrikshKatna @Visa bro from where u studied hld basics that were asked in your interview?

[Dhacker @dhacker1_]

Day 44 ✅ | #SDESheetChallenge
→ Binary Tree to Doubly Linked List
→ Find Median in a Data Stream
→ K-th Largest Element in a Stream

Learned tree-to-DLL conversion and heap-based stream processing today.
Patterns > memorization 🧠
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 43 ✅ | #SDESheetChallenge
→ Two Sum in BST
→ BST Iterator
→ Size of the Largest BST in a Binary Tree
→ Serialize & Deserialize Binary Tree

Learned BST iterators, advanced DFS on trees, and tree serialization techniques today.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 42 ✅ | #SDESheetChallenge
→ Floor in a BST
→ Ceil in a BST
→ Find K-th Smallest Element in BST
→ K-th Smallest & Largest Element in BST

Learned floor/ceil queries and how inorder traversal makes order-statistic problems in BSTs efficient.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 41 ✅ | #SDESheetChallenge
→ Construct BST from Preorder Traversal
→ Check if Tree is BST
→ LCA in BST
→ Inorder Successor ,Predecessor in BST

Learned BST validation, construction and how to exploit the BST property for efficient searching
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 40 ✅ | #SDESheetChallenge
→ Populating Next Right Pointers in Each Node
→ Search in BST
→ Construct BST from Given Keys

Started the BST section by learning level-wise linking, efficient searching, and recursive BST construction.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 39 ✅ | #SDESheetChallenge
→ Symmetric Binary Tree
→ Flatten Binary Tree to Linked List
→ Check for Symmetrical Binary Trees
→ Children Sum Property in Binary Tree

Learned mirror recursion, tree flattening and structural tree transformation

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 38 ✅ | #SDESheetChallenge
→ Maximum Path Sum in Binary Tree
→ Construct Binary Tree from Preorder & Inorder
→ Construct Binary Tree from Postorder & Inorder

Learned recursive tree reconstruction and DFS-based maximum path computation today.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 37 ✅ | #SDESheetChallenge
→ LCA in Binary Tree
→ Check if Two Trees are Identical
→ Zig Zag Traversal
→ Boundary Traversal

Learned recursive tree comparison, divide-and-conquer for LCA, and multiple tree traversal patterns today.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 36 ✅ | #SDESheetChallenge
→ Level Order Traversal
→ Maximum Depth of Binary Tree
→ Diameter of Binary Tree
→ Check for Balanced Binary Tree

Learned BFS traversal and how a single DFS can solve multiple tree problems efficiently.
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 35 | #SDESheetChallenge
→ Pre, In & Postorder in One Traversal
→ Vertical Order Traversal
→ Print Root to Leaf Paths
→ Maximum Width of Binary Tree
Learned single stack traversal, vertical ordering, DFS path generation, and width calculation
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 34 ✅ | #SDESheetChallenge
→ Morris Preorder Traversal
→ Right & Left View of Binary Tree
→ Bottom View of Binary Tree
→ Top View of Binary Tree

Learned O(1) space preorder traversal and how to compute different views of a binary tree.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 33 ✅ | #SDESheetChallenge
→ Inorder Traversal
→ Preorder Traversal
→ Postorder Traversal
→ Morris Inorder Traversal

Started the Binary Trees section by learning recursive traversals and the O(1) space Morris Traversal.

@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 32 ✅ | #SDESheetChallenge
→ Valid Anagram
→ Count and Say
→ Compare Version Numbers

Learned frequency counting, recursive sequence generation, and robust string parsing today.
Patterns > memorization 🧠
@takeUforward_
@striver_79

#DSA #LeetCode #CPP #Strings

[Dhacker @dhacker1_]

Day 31 ✅ | #SDESheetChallenge
→ Z Function
→ KMP Algorithm (LPS Array)
→ Minimum Insertions to Make String Palindrome

Learned advanced string preprocessing and dynamic programming on strings today.
Patterns > memorization 🧠
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 30 ✅ | #SDESheetChallenge
→ Implement ATOI (String to Integer)
→ Longest Common Prefix
→ Rabin-Karp Algorithm

Learned string parsing, prefix comparison, and rolling hash based pattern matching today.
Patterns > memorization 🧠
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 29 ✅ | #SDESheetChallenge
→ Reverse Every Word in a String
→ Longest Palindrome in a String
→ Roman to Integer

Learned string traversal, palindrome expansion, and efficient Roman numeral parsing today.
Patterns > memorization 🧠
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 28 ✅ | #SDESheetChallenge
→ Stock Span Problem
→ Maximum of Minimums for Every Window Size
→ Celebrity Problem

Learned monotonic stack techniques, previous/next smaller element patterns, and candidate elimination today.
@takeUforward_
@striver_79

[Dhacker @dhacker1_]

Day 27 ✅ | #SDESheetChallenge
→ Largest Rectangle in a Histogram
→ Sliding Window Maximum
→ Implement Min Stack
→ Rotten Oranges

Learned monotonic stacks, deque-based sliding windows, constant-time minimum retrieval, and multi-source BFS today.
Patterns > memorization 🧠

[Dhacker @dhacker1_]

Day 26 ✅ | #SDESheetChallenge
→ Next Smaller Element
→ LRU Cache
→ LFU Cache

Learned monotonic stacks and how hash maps + linked lists power efficient cache implementations.
Patterns > memorization 🧠
@takeUforward_
@striver_79

#DSA #LeetCode #CPP #Stack #CacheDesign