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446 problems confirmed in interviews | 1483 total tagged

Problem titles link to LeetCode. Interview mention counts are derived from our analysis of public discussion posts.

Priority List (confirmed in interviews)

# Problem Difficulty Tags Seen LC Editorial Video
1 House Robber Medium DP 12x LC
2 Longest Substring Without Repeating Characters Medium Tree 10x LC
3 Number of Islands Medium Graph 9x LC
4 Two Sum Easy Array / Two Pointers 8x LC
5 Search in Rotated Sorted Array Medium Binary Search 8x LC
6 Maximum Subarray Medium Array / Two Pointers 8x LC
7 Course Schedule Medium Graph 8x LC
8 Subarray Sum Equals K Medium Array / Two Pointers 8x LC
9 Container With Most Water Medium Array / Two Pointers 7x LC
10 Merge Intervals Medium Array, Sorting 7x LC
11 Unique Paths Medium DP 7x LC
12 Largest Rectangle in Histogram Hard Stack / Queue 7x LC
13 Best Time to Buy and Sell Stock Easy Other 7x LC
14 Find Minimum in Rotated Sorted Array Medium Other 7x LC
15 Sliding Window Maximum Hard Array, Queue, Sliding Window 7x LC
16 Target Sum Medium Other 7x LC
17 3Sum Medium Array, Two Pointers, Sorting 6x LC
18 Valid Parentheses Easy Stack / Queue 6x LC
19 Permutations Medium Backtracking 6x LC
20 Group Anagrams Medium Array, Hash Table, String 6x LC
21 Climbing Stairs Easy DP 6x LC
22 Sort Colors Medium Array, Two Pointers, Sorting 6x LC
23 Minimum Window Substring Hard Tree 6x LC
24 Binary Tree Level Order Traversal Medium Tree 6x LC
25 Word Ladder Hard Other 6x LC
26 Word Break Medium DP 6x LC
27 Course Schedule II Medium Graph 6x LC
28 Product of Array Except Self Medium Array / Two Pointers 6x LC
29 Longest Increasing Subsequence Medium DP 6x LC
30 Coin Change Medium DP 6x LC
31 Decode String Medium String 6x LC
32 Longest Palindromic Substring Medium Tree 5x LC
33 Jump Game II Medium DP 5x LC
34 Jump Game Medium DP 5x LC
35 Validate Binary Search Tree Medium Tree, Depth-First Search, Binary Search Tree 5x LC
36 Valid Palindrome Easy String 5x LC
37 Maximum Product Subarray Medium Array, Dynamic Programming 5x LC
38 Majority Element Easy Array, Hash Table, Divide and Conquer 5x LC
39 Minimum Size Subarray Sum Medium Array / Two Pointers 5x LC
40 House Robber II Medium DP 5x LC
41 Meeting Rooms II Medium Intervals 5x LC
42 Top K Frequent Elements Medium Heap / PQ 5x LC
43 Binary Search Easy Array, Binary Search 5x LC
44 Rotting Oranges Medium Graph 5x LC
45 Capacity To Ship Packages Within D Days Medium Other 5x LC
46 Median of Two Sorted Arrays Hard Other 4x LC
47 Merge k Sorted Lists Hard Heap / PQ 4x LC
48 Combination Sum Medium Backtracking 4x LC
49 Trapping Rain Water Hard Array / Two Pointers 4x LC
50 Decode Ways Medium DP 4x LC
51 Maximum Depth of Binary Tree Easy Tree 4x LC
52 Binary Tree Maximum Path Sum Hard Tree 4x LC
53 Longest Consecutive Sequence Medium Array, Hash Table, Union-Find 4x LC
54 LRU Cache Medium HashMap / Design 4x LC
55 Contains Duplicate Easy Other 4x LC
56 Valid Anagram Easy String 4x LC
57 Missing Number Easy Other 4x LC
58 Move Zeroes Easy Other 4x LC
59 Find Median from Data Stream Hard Heap / PQ 4x LC
60 Pacific Atlantic Water Flow Medium Other 4x LC
61 Longest Repeating Character Replacement Medium Sliding Window 4x LC
62 Contiguous Array Medium Other 4x LC
63 Diameter of Binary Tree Easy Tree 4x LC
64 Max Consecutive Ones III Medium Other 4x LC
65 Longest Common Subsequence Medium Other 4x LC
66 Longest Continuous Subarray With Absolute Diff Less Tha Medium Array / Two Pointers 4x LC
67 Add Two Numbers Medium Linked List 3x LC
68 Regular Expression Matching Hard String, Dynamic Programming, Recursion 3x LC
69 Longest Common Prefix Easy Other 3x LC
70 Letter Combinations of a Phone Number Medium Hash Table, String, Backtracking 3x LC
71 Remove Nth Node From End of List Medium Linked List, Two Pointers 3x LC
72 Generate Parentheses Medium String, Dynamic Programming, Backtracking 3x LC
73 Search Insert Position Easy Other 3x LC
74 N-Queens Hard Array, Backtracking 3x LC
75 Simplify Path Medium Other 3x LC
76 Subsets Medium Array, Backtracking, Bit Manipulation 3x LC
77 Word Search Medium Backtracking 3x LC
78 Same Tree Easy Tree 3x LC
79 Clone Graph Medium Graph 3x LC
80 Single Number Easy Other 3x LC

Graph (43 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Number of Islands Medium 9x LC
2 Course Schedule Medium 8x LC
3 Course Schedule II Medium 6x LC
4 Rotting Oranges Medium 5x LC
5 Clone Graph Medium 3x LC
6 Alien Dictionary Hard 3x LC
7 Number of Connected Components in an Undirected Graph Medium 3x LC
8 Graph Valid Tree Medium Depth-First Search, Breadth-First Search, Union-Find 2x LC
9 Is Graph Bipartite? Medium Depth-First Search, Breadth-First Search, Union-Find 2x LC
10 Reconstruct Itinerary Hard Array, String, Depth-First Search 1x LC
11 Evaluate Division Medium 1x LC
12 Bus Routes Hard 1x LC
13 Making A Large Island Hard 1x LC
14 Number of Islands II Hard 1x LC
15 Network Delay Time Medium Depth-First Search, Breadth-First Search, Graph Theory 1x LC
16 Shortest Cycle in a Graph Hard Breadth-First Search, Graph Theory 1x LC
17 Course Schedule Iii ? 1x LC
18 Minimum Number Of Days To Disconnect Island ? 1x LC
19 Island Perimeter Easy LC
20 Number of Distinct Islands Medium LC
21 Max Area of Island Medium LC
22 Number of Distinct Islands II Hard LC
23 Cheapest Flights Within K Stops Medium LC
24 Verifying an Alien Dictionary Easy LC
25 Number of Closed Islands Medium LC
26 Construct the Lexicographically Largest Valid Sequence Medium LC
27 Find if Path Exists in Graph Easy Depth-First Search, Breadth-First Search, Union-Find LC
28 Lexicographical Numbers Medium LC
29 K-th Smallest in Lexicographical Order Hard LC
30 Remove Max Number of Edges to Keep Graph Fully Traversa Hard LC
31 Number of Operations to Make Network Connected Medium LC
32 All Ancestors of a Node in a Directed Acyclic Graph Medium LC
33 Course Schedule IV Medium LC
34 The k-th Lexicographical String of All Happy Strings of Medium String, Backtracking LC
35 Minimum Cost Walk in Weighted Graph Hard LC
36 Largest Color Value in a Directed Graph Hard LC
37 Find Center of Star Graph Easy LC
38 Find the Lexicographically Largest String From the Box Medium Two Pointers, String, Enumeration LC
39 Lexicographically Smallest Equivalent String Medium LC
40 Using a Robot to Print the Lexicographically Smallest S Medium LC
41 Lexicographically Minimum String After Removing Stars Medium Hash Table, String, Stack LC
42 Reorder Routes to Make All Paths Lead to the City Zero Medium LC
43 Count Sub Islands Medium Array, Depth-First Search, Breadth-First Search LC

DP (36 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 House Robber Medium 12x LC
2 Unique Paths Medium 7x LC
3 Climbing Stairs Easy 6x LC
4 Word Break Medium 6x LC
5 Longest Increasing Subsequence Medium 6x LC
6 Coin Change Medium 6x LC
7 Jump Game II Medium 5x LC
8 Jump Game Medium 5x LC
9 House Robber II Medium 5x LC
10 Decode Ways Medium 4x LC
11 Regular Expression Matching Hard String, Dynamic Programming, Recursion 3x LC
12 Unique Paths II Medium 2x LC
13 Minimum Path Sum Medium 2x LC
14 Maximum Profit in Job Scheduling Hard 2x LC
15 Wildcard Matching Hard 1x LC
16 Edit Distance Medium 1x LC
17 Word Break II Hard Array, Hash Table, String 1x LC
18 House Robber III Medium Dynamic Programming, Tree, Depth-First Search 1x LC
19 Min Cost Climbing Stairs Easy 1x LC
20 Jump Game Vii ? 1x LC
21 House Robber V Medium Array, Dynamic Programming 1x LC
22 Coin Change 2 ? 1x LC
23 One Edit Distance Medium LC
24 Dungeon Game Hard LC
25 Longest Increasing Path in a Matrix Hard LC
26 Decode Ways II Hard LC
27 Number of Longest Increasing Subsequence Medium LC
28 Minimum Path Cost in a Hidden Grid Medium LC
29 Unique Paths III Hard LC
30 House Robber IV Medium LC
31 Coin Change II Medium LC
32 Cherry Pickup Hard LC
33 Jump Game IV Hard LC
34 Cherry Pickup II Hard LC
35 Jump Game VI Medium LC
36 Maximum Profit from Trading Stocks with Discounts Hard LC

Tree (142 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Longest Substring Without Repeating Characters Medium 10x LC
2 Minimum Window Substring Hard 6x LC
3 Binary Tree Level Order Traversal Medium 6x LC
4 Longest Palindromic Substring Medium 5x LC
5 Validate Binary Search Tree Medium Tree, Depth-First Search, Binary Search Tree 5x LC
6 Maximum Depth of Binary Tree Easy 4x LC
7 Binary Tree Maximum Path Sum Hard 4x LC
8 Diameter of Binary Tree Easy 4x LC
9 Same Tree Easy 3x LC
10 Invert Binary Tree Easy Tree, Depth-First Search, Breadth-First Search 3x LC
11 Kth Smallest Element in a BST Medium 3x LC
12 Lowest Common Ancestor of a Binary Search Tree Medium 3x LC
13 Serialize and Deserialize Binary Tree Hard String, Tree, Depth-First Search 3x LC
14 Palindromic Substrings Medium 3x LC
15 Construct Binary Tree from Preorder and Inorder Travers Medium 2x LC
16 Balanced Binary Tree Easy Tree, Depth-First Search, Binary Tree 2x LC
17 Lowest Common Ancestor of a Binary Tree Medium 2x LC
18 Subtree of Another Tree Easy 2x LC
19 All Nodes Distance K in Binary Tree Medium 2x LC
20 Binary Tree Cameras Hard 2x LC
21 Count Good Nodes in Binary Tree Medium 2x LC
22 Count Complete Tree Nodes Easy 2x LC
23 Equal Score Substrings ? 2x LC
24 Find Leaves Of Binary Tree ? 2x LC
25 Binary Tree Inorder Traversal Easy Stack, Tree, Depth-First Search 1x LC
26 Convert Sorted Array to Binary Search Tree Easy 1x LC
27 Convert Sorted List to Binary Search Tree Medium 1x LC
28 Binary Tree Right Side View Medium 1x LC
29 Implement Trie (Prefix Tree) Medium 1x LC
30 Minimum Height Trees Medium 1x LC
31 Delete Node in a BST Medium Tree, Binary Search Tree, Binary Tree 1x LC
32 Find Mode in Binary Search Tree Easy 1x LC
33 Minimum Absolute Difference in BST Easy 1x LC
34 Boundary of Binary Tree Medium 1x LC
35 Two Sum IV - Input is a BST Easy 1x LC
36 Search in a Binary Search Tree Easy 1x LC
37 Range Sum of BST Easy 1x LC
38 Construct Binary Search Tree from Preorder Traversal Medium 1x LC
39 Maximum Level Sum of a Binary Tree Medium 1x LC
40 Shortest Path in a Grid with Obstacles Elimination Hard 1x LC
41 All Elements in Two Binary Search Trees Medium 1x LC
42 Maximum Sum BST in Binary Tree Hard 1x LC
43 Lowest Common Ancestor of a Binary Tree II Medium 1x LC
44 Count Nodes Equal to Average of Subtree Medium 1x LC
45 Unique Binary Search Trees Medium 1x LC
46 Insert into a Binary Search Tree Medium Tree, Binary Search Tree, Binary Tree 1x LC
47 Construct Binary Tree from Preorder and Postorder Trave Medium Array, Hash Table, Divide and Conquer 1x LC
48 Construct String from Binary Tree Medium 1x LC
49 Construct Binary Tree from Inorder and Postorder Traver Medium 1x LC
50 Repeated Substring Pattern Easy 1x LC

...and 92 more in this category.

Array / Two Pointers (74 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Two Sum Easy 8x LC
2 Maximum Subarray Medium 8x LC
3 Subarray Sum Equals K Medium 8x LC
4 Container With Most Water Medium 7x LC
5 Product of Array Except Self Medium 6x LC
6 Maximum Product Subarray Medium Array, Dynamic Programming 5x LC
7 Minimum Size Subarray Sum Medium 5x LC
8 Trapping Rain Water Hard 4x LC
9 Longest Continuous Subarray With Absolute Diff Less Tha Medium 4x LC
10 Subarray Sums Divisible by K Medium 3x LC
11 Subarrays with K Different Integers Hard 3x LC
12 Merge Sorted Array Easy 2x LC
13 Two Sum II - Input Array Is Sorted Medium 2x LC
14 Count Number of Nice Subarrays Medium 2x LC
15 Count of Interesting Subarrays Medium 2x LC
16 Maximum Number Of Non Overlapping Subarrays With Sum Eq ? 2x LC
17 Maximum Subarray Sum With One Deletion ? 2x LC
18 Maximum Subarray Xor With Bounded Range ? 2x LC
19 Remove Duplicates from Sorted Array Easy 1x LC
20 Remove Duplicates from Sorted Array II Medium 1x LC
21 Trapping Rain Water II Hard Array, Breadth-First Search, Heap (Priority Queue) 1x LC
22 Maximum Average Subarray I Easy 1x LC
23 Subarray Product Less Than K Medium Array, Binary Search, Sliding Window 1x LC
24 Shortest Subarray with Sum at Least K Hard 1x LC
25 Sum of Subarray Minimums Medium 1x LC
26 Length of Longest Subarray With at Most K Frequency Medium Array, Hash Table, Sliding Window 1x LC
27 Shortest Unsorted Continuous Subarray Medium 1x LC
28 Sum of Subarray Ranges Medium 1x LC
29 Number of Zero-Filled Subarrays Medium 1x LC
30 Bitwise ORs of Subarrays Medium 1x LC
31 Minimum Number of Increments on Subarrays to Form a Tar Hard 1x LC
32 Maximum Length of Repeated Subarray Medium Array, Binary Search, Dynamic Programming 1x LC
33 Number of Subarrays With GCD Equal to K Medium Array, Math, Number Theory 1x LC
34 Number Of Subarrays With Lcm Equal To K ? 1x LC
35 Closest Subarray Bitwise And To Target ? 1x LC
36 Count Good Subarrays ? 1x LC
37 Maximum Subarray Min Product ? 1x LC
38 Count Subarrays With Cost Less Than or Equal to K Medium Array, Queue, Monotonic Queue 1x LC
39 Find Maximum Balanced XOR Subarray Length Medium Array, Hash Table, Bit Manipulation 1x LC
40 Count The Number Of Beautiful Subarrays ? 1x LC
41 Count Prime Gap Balanced Subarrays ? 1x LC
42 Maximum Good Subarray Sum ? 1x LC
43 Maximum Size Subarray Sum Equals k Medium LC
44 Continuous Subarray Sum Medium LC
45 Maximum Sum of 3 Non-Overlapping Subarrays Hard LC
46 Maximum Sum Circular Subarray Medium LC
47 Binary Subarrays With Sum Medium Array, Hash Table, Sliding Window LC
48 Make Two Arrays Equal by Reversing Subarrays Easy LC
49 Longest Subarray of 1's After Deleting One Element Medium LC
50 K Radius Subarray Averages Medium Array, Sliding Window LC

...and 24 more in this category.

Sliding Window (4 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Sliding Window Maximum Hard Array, Queue, Sliding Window 7x LC
2 Longest Repeating Character Replacement Medium 4x LC
3 Sliding Window Median Hard LC
4 Minimum Window Subsequence Hard LC

Intervals (12 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Merge Intervals Medium Array, Sorting 7x LC
2 Meeting Rooms II Medium 5x LC
3 Meeting Rooms III Hard 2x LC
4 Intervals Between Identical Elements ? 2x LC
5 Insert Interval Medium 1x LC
6 Non-overlapping Intervals Medium 1x LC
7 Meeting Rooms Easy Array, Sorting LC
8 Interval List Intersections Medium Array, Two Pointers, Sweep Line LC
9 Remove Covered Intervals Medium LC
10 Divide Intervals Into Minimum Number of Groups Medium LC
11 My Calendar I Medium LC
12 Count Odd Numbers in an Interval Range Easy LC

Heap / PQ (9 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Top K Frequent Elements Medium 5x LC
2 Merge k Sorted Lists Hard 4x LC
3 Find Median from Data Stream Hard 4x LC
4 Kth Largest Element in an Array Medium 2x LC
5 Top K Frequent Words Medium 1x LC
6 Reorganize String Medium 1x LC
7 Task Scheduler Medium LC
8 Kth Largest Element in a Stream Easy LC
9 Task Scheduler II Medium LC

Stack / Queue (26 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Largest Rectangle in Histogram Hard 7x LC
2 Valid Parentheses Easy 6x LC
3 Generate Parentheses Medium String, Dynamic Programming, Backtracking 3x LC
4 Asteroid Collision Medium 3x LC
5 Daily Temperatures Medium Array, Stack, Monotonic Stack 3x LC
6 Min Stack Medium 2x LC
7 Valid Parenthesis String Medium 2x LC
8 Longest Valid Parentheses Hard String, Dynamic Programming, Stack 1x LC
9 Basic Calculator Hard 1x LC
10 Implement Queue using Stacks Easy 1x LC
11 Max Stack Hard 1x LC
12 Maximum Frequency Stack Hard 1x LC
13 Basic Calculator II Medium LC
14 Different Ways to Add Parentheses Medium LC
15 Remove Invalid Parentheses Hard String, Backtracking, Breadth-First Search LC
16 Basic Calculator III Hard LC
17 Minimum Add to Make Parentheses Valid Medium LC
18 Remove Outermost Parentheses Easy LC
19 Minimum Remove to Make Valid Parentheses Medium String, Stack LC
20 Minimum Insertions to Balance a Parentheses String Medium LC
21 Maximum Nesting Depth of the Parentheses Easy LC
22 Score of Parentheses Medium LC
23 Implement Stack using Queues Easy LC
24 Check if a Parentheses String Can Be Valid Medium LC
25 Validate Stack Sequences Medium LC
26 Maximum Height by Stacking Cuboids Hard LC

HashMap / Design (9 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Group Anagrams Medium Array, Hash Table, String 6x LC
2 LRU Cache Medium 4x LC
3 First Unique Character in a String Easy 3x LC
4 Design Hit Counter Medium 2x LC
5 Insert Delete GetRandom O(1) Medium 1x LC
6 First Unique Number Medium 1x LC
7 Insert Delete GetRandom O(1) - Duplicates allowed Hard LC
8 LFU Cache Hard LC
9 Design HashMap Easy LC

Binary Search (6 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Search in Rotated Sorted Array Medium 8x LC
2 Binary Search Easy Array, Binary Search 5x LC
3 Find First and Last Position of Element in Sorted Array Medium LC
4 Sqrt(x) Easy Math, Binary Search LC
5 Search in Rotated Sorted Array II Medium Array, Binary Search LC
6 Split Array Largest Sum Hard LC

String (27 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Decode String Medium 6x LC
2 Valid Palindrome Easy 5x LC
3 Valid Anagram Easy 4x LC
4 Find All Anagrams in a String Medium 3x LC
5 Palindrome Partitioning Medium String, Dynamic Programming, Backtracking 2x LC
6 Palindrome Linked List Easy 2x LC
7 Longest Palindromic Subsequence Medium String, Dynamic Programming 2x LC
8 Valid Palindrome II Easy Two Pointers, String, Greedy 2x LC
9 Find the Closest Palindrome Hard Math, String 2x LC
10 Palindrome Number Easy 1x LC
11 Encode and Decode Strings Medium Array, String, Design 1x LC
12 Minimum Insertion Steps to Make a String Palindrome Hard 1x LC
13 String to Integer (atoi) Medium LC
14 Text Justification Hard Array, String, Simulation LC
15 Palindrome Permutation Easy LC
16 Palindrome Permutation II Medium LC
17 Longest Palindrome Easy Hash Table, String, Greedy LC
18 Valid Palindrome III Hard LC
19 Unique Length-3 Palindromic Subsequences Medium LC
20 Shortest Palindrome Hard LC
21 Construct K Palindrome Strings Medium LC
22 Palindrome Partitioning II Hard String, Dynamic Programming LC
23 Longest Palindrome by Concatenating Two Letter Words Medium LC
24 Prime Palindrome Medium LC
25 Palindrome Pairs Hard LC
26 Find Resultant Array After Removing Anagrams Easy LC
27 Valid Palindrome IV Medium Two Pointers, String LC

Backtracking (29 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Permutations Medium 6x LC
2 Combination Sum Medium 4x LC
3 Letter Combinations of a Phone Number Medium Hash Table, String, Backtracking 3x LC
4 N-Queens Hard Array, Backtracking 3x LC
5 Subsets Medium Array, Backtracking, Bit Manipulation 3x LC
6 Word Search Medium 3x LC
7 Partition Equal Subset Sum Medium 3x LC
8 Permutation in String Medium 3x LC
9 Next Permutation Medium Array, Two Pointers 2x LC
10 Sudoku Solver Hard 2x LC
11 Combination Sum II Medium 2x LC
12 Combination Sum IV Medium 2x LC
13 Combinations Medium 1x LC
14 Subsets II Medium 1x LC
15 Word Search II Hard Array, String, Backtracking 1x LC
16 Partition to K Equal Sum Subsets Medium 1x LC
17 Sum of All Subset XOR Totals Easy 1x LC
18 Valid Sudoku Medium LC
19 Permutations II Medium Array, Backtracking, Sorting LC
20 Letter Case Permutation Medium LC
21 Build Array from Permutation Easy Array, Simulation LC
22 Permutation Sequence Hard LC
23 N-Queens II Hard LC
24 Word Subsets Medium LC
25 Count Number of Maximum Bitwise-OR Subsets Medium LC
26 Largest Divisible Subset Medium LC
27 Count Number of Balanced Permutations Hard LC
28 Partition Array into Two Equal Product Subsets Medium LC
29 Count the Number of Computer Unlocking Permutations Medium LC

Matrix / Grid (27 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Rotate Image Medium 2x LC
2 Spiral Matrix Medium 2x LC
3 Matrix Block Sum ? 2x LC
4 Set Matrix Zeroes Medium 1x LC
5 Search a 2D Matrix Medium 1x LC
6 Kth Smallest Element in a Sorted Matrix Medium 1x LC
7 Spiral Matrix II Medium LC
8 Search a 2D Matrix II Medium Array, Binary Search, Divide and Conquer LC
9 Game of Life Medium LC
10 Sparse Matrix Multiplication Medium LC
11 01 Matrix Medium LC
12 Toeplitz Matrix Easy LC
13 Shortest Path in Binary Matrix Medium LC
14 Count Negative Numbers in a Sorted Matrix Easy LC
15 Find the Kth Smallest Sum of a Matrix With Sorted Rows Hard LC
16 Largest Local Values in a Matrix Easy LC
17 Spiral Matrix III Medium Array, Matrix, Simulation LC
18 Reshape the Matrix Easy LC
19 Determine Whether Matrix Can Be Obtained By Rotation Easy Array, Matrix LC
20 Spiral Matrix IV Medium LC
21 Transpose Matrix Easy Array, Matrix, Simulation LC
22 Rank Transform of a Matrix Hard Array, Union-Find, Graph Theory LC
23 Sort Matrix by Diagonals Medium LC
24 Special Positions in a Binary Matrix Easy LC
25 The K Weakest Rows in a Matrix Easy LC
26 Maximum Matrix Sum Medium LC
27 Matrix Similarity After Cyclic Shifts Easy LC

Linked List (28 problems)

# Problem Difficulty Tags Seen LC Editorial Video
1 Add Two Numbers Medium 3x LC
2 Linked List Cycle Easy Hash Table, Linked List, Two Pointers 3x LC
3 Linked List Cycle II Medium 3x LC
4 Merge Two Sorted Lists Easy 2x LC
5 Reverse Linked List Easy 2x LC
6 Middle of the Linked List Easy 2x LC
7 Intersection of Two Linked Lists Easy 1x LC
8 Delete Node in a Linked List Medium 1x LC
9 Odd Even Linked List Medium 1x LC
10 Flatten a Multilevel Doubly Linked List Medium 1x LC
11 Merge In Between Linked Lists Medium 1x LC
12 Split Linked List in Parts Medium 1x LC
13 Swap Nodes in Pairs Medium LC
14 Reverse Linked List II Medium LC
15 Remove Linked List Elements Easy LC
16 Add Two Numbers II Medium LC
17 Swapping Nodes in a Linked List Medium Linked List, Two Pointers LC
18 Insert into a Sorted Circular Linked List Medium LC
19 Remove Zero Sum Consecutive Nodes from Linked List Medium LC
20 Convert Binary Number in a Linked List to Integer Easy LC
21 Remove Nodes From Linked List Medium LC
22 Insert Greatest Common Divisors in Linked List Medium Linked List, Math, Number Theory LC
23 Delete the Middle Node of a Linked List Medium LC
24 Linked List Random Node Medium LC
25 Maximum Twin Sum of a Linked List Medium LC
26 Delete Nodes From Linked List Present in Array Medium Array, Hash Table, Linked List LC
27 Design Linked List Medium LC
28 Linked List Components Medium LC