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SDE SHEET - Code Quest 135+

Crafted for MAANG aspirants, this DSA sheet features 135+ challenges—from warm-ups to hard-level problems. Each question will have a detailed video lecture on our YouTube channel. (Video links will be added shortly) Making it your ultimate last-minute prep companion.

Arrays & Hashing

PRACTICE SOLUTION
Two Sum
Valid Anagram
Contains Duplicate
Maximum Points You Can Obtain
Move Zeros
Check if Array Is Sorted and Rotated
Find the Duplicate Number
Product of Array Except Self
First Missing Positive
Best Time to Buy and Sell Stock
Longest Consecutive Sequence
Merge Intervals

Matrix

PRACTICE SOLUTION
Set Matrix Zeroes
Spiral Matrix
Rotate Image
Valid Sudoku

Two Pointers

PRACTICE SOLUTION
Container With Most Water
Reverse Words in a String
Trapping Rain Water
3Sum
Find the Duplicate Number
Sort Colors
Two Sum II – Input Array Is Sorted

Sliding Window

PRACTICE SOLUTION
Longest Substring Without Repeating Characters
Minimum Window Substring
Maximum Subarray Sum
Subarray Sum Equals K
Running Sum of 1D Array
Permutation in String
Longest Repeating Character Replacement
Number of Substrings Containing All Three Characters
Count Occurrences of Anagrams
Fixed-Size Sliding Window Problems

Strings

PRACTICE SOLUTION
Minimum Number of Bracket Reversals
Rabin-Karp Algorithm
Z-Function
Longest Palindromic Substring (Centered Expansion)
Palindrome Partitioning II
KMP Algorithm (LPS Array)

Stack & Queue

PRACTICE SOLUTION
Valid Parentheses
Next greater Element II
Min Stack
Evaluate Reverse Polish Notation
Generate Parentheses
Daily Temperatures
Largest Rectangle in Histogram
Sliding Window Maximum
LRU Cache

Linked Lists

Reverse Linked List
Merge Two Sorted Lists
Remove Nth Node From End of List
Add Two Numbers
Linked List Cycle
Palindrome Linked List

Binary Tree

PRACTICE SOLUTION
Invert Binary Tree
Maximum Depth of Binary Tree
Same Tree
Subtree of Another Tree
Binary Tree Level Order Traversal
Binary Tree Right Side View
Path Sum
Path Sum II
Binary Tree Maximum Path Sum
Serialize and Deserialize Binary Tree
Flatten Binary Tree to Linked List
Populating Next Right Pointers in Each Node

Priority Queues (Heaps)

PRACTICE SOLUTION
Kth Largest Element in an Array
Find Median from Data Stream
Merge K Sorted Lists
Top K Frequent Elements
K Closest Points to Origin

BST

PRACTICE SOLUTION
Validate Binary Search Tree
Kth Smallest Element in a BST
Lowest Common Ancestor of a BST
Search in a Binary Search Tree
Insert into a Binary Search Tree
Delete Node in a BST
Recover Binary Search Tree
Convert Sorted Array to BST
Construct BST from Preorder Traversal

Recursion & Backtracking

PRACTICE SOLUTION
Fibonacci Number
Pow(x, n)
Subsets
Subsets II
Permutations
Permutations II
Combinations
Combination Sum
Combination Sum II
Word Search
N-Queens
Sudoku Solver

TRIE

PRACTICE SOLUTION
Implement Trie (Prefix Tree)
Design Add and Search Words Data Structure
Word Search II
Replace Words
Longest Word in Dictionary
Palindrome Pairs

Graphs

PRACTICE SOLUTION
Number of Islands
Max Area of Island
Clone Graph
Rotting Oranges
Course Schedule
Course Schedule II
Is Graph Bipartite?
Redundant Connection
Network Delay Time
Min Cost to Connect All Points
Word Ladder
Number of Connected Components
Find Eventual Safe States
Strongly Connected Components

Dynamic Programming

PRACTICE SOLUTION
Climbing Stairs
House Robber
House Robber II
Maximum Product Subarray
Partition Equal Subset Sum
Coin Change
Combination Sum IV
Target Sum
Longest Common Subsequence
Longest Increasing Subsequence
Longest Palindromic Substring
Palindromic Substrings
Unique Paths
Unique Paths II
Minimum Path Sum
Count Square Submatrices with All Ones
Best Time to Buy and Sell Stock IV
Best Time to Buy and Sell Stock III
Best Time to Buy and Sell Stock with Cooldown
Word Break
Decode Ways
Interleaving String
Burst Balloons
Super Egg Drop

Greedy

PRACTICE SOLUTION
Jump Game II
Gas Station
Assign Cookies
Non-overlapping Intervals

Advanced

PRACTICE SOLUTION
Number of Islands II (DSU)
Find Critical & Pseudo-Critical Edges in MST
Range Sum Query - Mutable (Segment Tree)
Morris Traversal
Preict the Winner (Game Theory)
Stone Game

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