Grind 169

An expanded interview set beyond Blind 75 — deeper coverage of graphs, DP, heaps, and design problems used by FAANG and high-growth startups.

170 problems in catalog

#	Title	Difficulty	Topics
1	Two Sum	Easy	hash table
20	Valid Parentheses	Easy	stack
21	Merge Two Sorted Lists	Easy	linked list
121	Best Time to Buy and Sell Stock	Easy	array
125	Valid Palindrome	Easy	string
226	Invert Binary Tree	Easy	tree
242	Valid Anagram	Easy	string
704	Binary Search	Easy	binary search
733	Max Area of Island	Easy	depth first search
235	Lowest Common Ancestor of a Binary Search Tree	Easy	binary search tree
110	Balanced Binary Tree	Easy	recursion
141	Linked List Cycle	Easy	two pointers
232	Implement Queue using Stacks	Easy	stack
278	First Bad Version	Easy	binary search
383	Ransom Note	Easy	string
70	Climbing Stairs	Easy	dynamic programming
409	Longest Palindrome	Easy	hash table
206	Reverse Linked List	Easy	linked list
169	Majority Element	Easy	array
67	Add Binary	Easy	string
543	Diameter of Binary Tree	Easy	tree
876	Middle of the Linked List	Easy	two pointers
104	Maximum Depth of Binary Tree	Easy	recursion
217	Contains Duplicate	Easy	hash table
53	Maximum Subarray	Easy	dynamic programming
57	Insert Interval	Hard	sort
542	01 Matrix	Medium	breadth first search
973	K Closest Points to Origin	Easy	sort
3	Longest Substring Without Repeating Characters	Medium	hash table
15	3 Sum	Medium	two pointers
102	Binary Tree Level Order Traversal	Easy	breadth first search
133	Clone Graph	Medium	breadth first search
150	Evaluate Reverse Polish Notation	Medium	stack
207	Course Schedule	Medium	breadth first search
208	Implement Trie (Prefix Tree)	Medium	tree
322	Coin Change	Medium	dynamic programming
238	Product of Array Except Self	Medium	array
155	Min Stack	Easy	stack
98	Validate Binary Search Tree	Medium	recursion
200	Number of Islands	Medium	depth first search
994	Rotting Oranges	Easy	breadth first search
33	Search in Rotated Sorted Array	Medium	binary search
39	Combination Sum	Medium	backtracking
46	Permutations	Medium	backtracking
56	Merge Intervals	Hard	sort
236	Lowest Common Ancestor of a Binary Tree	Medium	depth first search
981	Time Based Key-Value Store	Medium	binary search
721	Accounts Merge	Medium	hash table
75	Sort Colors	Medium	sort
139	Word Break	Medium	dynamic programming
416	Partition Equal Subset Sum	Medium	dynamic programming
8	String to Integer (atoi)	Easy	string
54	Spiral Matrix	Medium	array
78	Subsets	Medium	backtracking
199	Binary Tree Right Side View	Medium	depth first search
5	Longest Palindromic Substring	Medium	string
62	Unique Paths	Medium	dynamic programming
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	recursion
11	Container With Most Water	Medium	greedy
17	Letter Combinations of a Phone Number	Medium	backtracking
79	Word Search	Medium	backtracking
438	Find All Anagrams in a String	Easy	hash table
310	Minimum Height Trees	Medium	breadth first search
621	Task Scheduler	Medium	greedy
146	LRU Cache	Hard	design
230	Kth Smallest Element in a BST	Medium	binary search tree
739	Daily Temperatures	Medium	stack
198	House Robber	Easy	dynamic programming
134	Gas Station	Medium	greedy
31	Next Permutation	Medium	array
36	Valid Sudoku	Easy	hash table
49	Group Anagrams	Medium	hash table
152	Maximum Product Subarray	Medium	dynamic programming
417	Pacific Atlantic Water Flow	Medium	depth first search
19	Remove Nth Node From End of List	Medium	two pointers
287	Find the Duplicate Number	Hard	two pointers
347	Top K Frequent Elements	Medium	sort
210	Course Schedule II	Medium	breadth first search
24	Swap Nodes in Pairs	Easy	linked list
113	Path Sum II	Medium	depth first search
128	Longest Consecutive Sequence	Hard	array
189	Rotate Array	Easy	array
191	Number of 1 Bits	Easy	bit manipulation
136	Single Number	Easy	bit manipulation
234	Palindrome Linked List	Easy	linked list
283	Move Zeroes	Easy	two pointers
221	Maximal Square	Medium	dynamic programming
48	Rotate Image	Medium	array
103	Binary Tree Zigzag Level Order Traversal	Medium	breadth first search
362	Design Hit Counter	Medium	design
437	Path Sum III	Easy	recursion
50	Pow(x, n)	Medium	math
74	Search a 2D Matrix	Medium	binary search
179	Largest Number	Medium	sort
394	Decode String	Medium	stack
253	Meeting Rooms II	Medium	sort
7	Reverse Integer	Easy	math
73	Set Matrix Zeroes	Medium	array
143	Reorder List	Medium	two pointers
271	Encode and Decode Strings	Medium	string
787	Cheapest Flights Within K Stops	Medium	breadth first search
863	All Nodes Distance K in Binary Tree	Medium	tree
16	3 Sum Closest	Medium	two pointers
61	Rotate List	Medium	linked list
153	Find Minimum in Rotated Sorted Array	Medium	binary search
227	Basic Calculator II	Medium	stack
377	Combination Sum IV	Medium	dynamic programming
380	Insert Delete GetRandom O(1)	Hard	design
435	Non-overlapping Intervals	Medium	greedy
76	Minimum Window Substring	Hard	hash table
42	Trapping Rain Water	Hard	greedy
84	Largest Rectangle in Histogram	Hard	stack
127	Word Ladder	Medium	breadth first search
224	Basic Calculator	Hard	stack
1235	Maximum Profit in Job Scheduling	Hard	dynamic programming
23	Merge k Sorted Lists	Hard	linked list
84	Largest Rectangle in Histogram	Hard	stack
126	Word Ladder II	Hard	backtracking
297	Serialize and Deserialize Binary Tree	Hard	tree
42	Trapping Rain Water	Hard	greedy
295	Find Median from Data Stream	Hard	binary heap
212	Word Search II	Hard	backtracking
149	Max Points on a Line	Hard	hash table
51	N-Queens	Hard	backtracking
239	Sliding Window Maximum	Hard	queue
76	Minimum Window Substring	Hard	hash table
269	Alien Dictionary	Hard	breadth first search
815	Bus Routes	Medium	breadth first search
1293	Shortest Path in a Grid with Obstacles Elimination	Hard	breadth first search
778	Swim in Rising Water	Hard	array
1192	Critical Connections in a Network	Medium	depth first search
329	Longest Increasing Path in a Matrix	Hard	depth first search
588	Design In-Memory File System	Hard	design
759	Employee Free Time	Hard	greedy
564	Find the Closest Palindrome	Hard	string
1044	Longest Duplicate Substring	Hard	binary search
857	Minimum Cost to Hire K Workers	Hard	binary heap
2050	Parallel Courses III	Medium	breadth first search
458	Poor Pigs	Easy	math
818	Race Car	Hard	dynamic programming
864	Shortest Path to Get All Keys	Hard	breadth first search
773	Sliding Puzzle	Hard	breadth first search
664	Strange Printer	Hard	dynamic programming
248	Strobogrammatic Number III	Hard	math
552	Student Attendance Record II	Hard	dynamic programming
887	Super Egg Drop	Hard	math
218	The Skyline Problem	Hard	sort
140	Word Break II	Hard	backtracking
488	Zuma Game	Hard	backtracking
312	Burst Balloons	Hard	dynamic programming
315	Count of Smaller Numbers After Self	Hard	tree
321	Create Maximum Number	Hard	greedy
352	Data Stream as Disjoint Intervals	Hard	binary search tree
642	Design Search Autocomplete System	Hard	design
282	Expression Add Operators	Hard	depth first search
295	Find Median from Data Stream	Hard	binary heap
403	Frog Jump	Hard	dynamic programming
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	design
329	Longest Increasing Path in a Matrix	Hard	depth first search
336	Palindrome Pairs	Hard	hash table
391	Perfect Rectangle	Hard	math
715	Range Module	Hard	design
301	Remove Invalid Parentheses	Hard	depth first search
335	Self Crossing	Hard	math
317	Shortest Distance from All Buildings	Hard	breadth first search
302	Smallest Rectangle Enclosing Black Pixels	Hard	binary search
410	Split Array Largest Sum	Hard	binary search
499	The Maze III	Hard	breadth first search
407	Trapping Rain Water II	Hard	binary heap
291	Word Pattern II	Hard	backtracking