LearnLeetGoat 222🚧 under constructionLeetGoatsoonFlashcardssoon

LeetGoat 222 🐐

After solving >3000 problems, these are the 222 questions I recommend to do for passing interviews! – leetgoat 🐐

LeetGoat DifficultyI found the LeetCode difficulties inaccurate, so I gave my own ratings!
LC Difficulty
Problem
Topics
Code
🐐🐐🐐🐐🐐
Easy
589. N-ary Tree Preorder Traversal
Tree
🐐🐐🐐🐐🐐
Easy
559. Maximum Depth of N-ary Tree
Tree
🐐🐐🐐🐐🐐
Easy
58. Length of Last Word
🐐🐐🐐🐐🐐
Easy
551. Student Attendance Record I
Sliding Window - Fixed
🐐🐐🐐🐐🐐
Easy
3502. Minimum Cost to Reach Every Position
Prefix / Suffix
🐐🐐🐐🐐🐐
Easy
2697. Lexicographically Smallest Palindrome
Two Pointers
🐐🐐🐐🐐🐐
Easy
121. Best Time to Buy and Sell Stock
Prefix / Suffix
🐐🐐🐐🐐🐐
Easy
383. Ransom Note
🐐🐐🐐🐐🐐
Easy
268. Missing Number
Math
🐐🐐🐐🐐🐐
Easy
1403. Minimum Subsequence in Non-Increasing Order
🐐🐐🐐🐐🐐
Easy
21. Merge Two Sorted Lists
Two PointersLinked List
🐐🐐🐐🐐🐐
Easy
1047. Remove All Adjacent Duplicates In String
Stacks
🐐🐐🐐🐐🐐
Easy
83. Remove Duplicates from Sorted List
Linked List
🐐🐐🐐🐐🐐
Easy
463. Island Perimeter
Matrix Graph
🐐🐐🐐🐐🐐
Medium
122. Best Time to Buy and Sell Stock II
🐐🐐🐐🐐🐐
Easy
205. Isomorphic Strings
🐐🐐🐐🐐🐐
Easy
3432. Count Partitions with Even Sum Difference
Prefix / Suffix
🐐🐐🐐🐐🐐
Easy
303. Range Sum Query - Immutable
Prefix / Suffix
🐐🐐🐐🐐🐐
Easy
507. Perfect Number
Number Theory
🐐🐐🐐🐐🐐
Easy
3114. Latest Time You Can Obtain After Replacing Characters
🐐🐐🐐🐐🐐
Easy
136. Single Number
Bit Operations
🐐🐐🐐🐐🐐
Easy
119. Pascal's Triangle II
Dynamic Programming
🐐🐐🐐🐐🐐
Easy
100. Same Tree
Tree
🐐🐐🐐🐐🐐
Easy
118. Pascal's Triangle
Constructive AlgorithmsDynamic Programming
🐐🐐🐐🐐🐐
Easy
104. Maximum Depth of Binary Tree
Tree
🐐🐐🐐🐐🐐
Easy
112. Path Sum
Tree
🐐🐐🐐🐐🐐
Easy
766. Toeplitz Matrix
🐐🐐🐐🐐🐐
Easy
141. Linked List Cycle
Linked ListTortoise and Hare
🐐🐐🐐🐐🐐
Medium
498. Diagonal Traverse
🐐🐐🐐🐐🐐
Medium
2964. Number of Divisible Triplet Sums
Two Pointers
🐐🐐🐐🐐🐐
Easy
1022. Sum of Root To Leaf Binary Numbers
TreeBit Operations
🐐🐐🐐🐐🐐
Medium
503. Next Greater Element II
Monostack
🐐🐐🐐🐐🐐
Medium
113. Path Sum II
Tree
🐐🐐🐐🐐🐐
Medium
213. House Robber II
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
3070. Count Submatrices with Top-Left Element and Sum Less Than k
2D Prefix / Suffix
🐐🐐🐐🐐🐐
Easy
374. Guess Number Higher or Lower
Binary Search
🐐🐐🐐🐐🐐
Medium
198. House Robber
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
970. Powerful Integers
Math
🐐🐐🐐🐐🐐
Medium
93. Restore IP Addresses
Backtracking
🐐🐐🐐🐐🐐
Medium
1695. Maximum Erasure Value
Sliding Window - Variable
🐐🐐🐐🐐🐐
Medium
2. Add Two Numbers
Linked List
🐐🐐🐐🐐🐐
Easy
1021. Remove Outermost Parentheses
Stacks
🐐🐐🐐🐐🐐
Easy
455. Assign Cookies
Two Pointers
🐐🐐🐐🐐🐐
Medium
3619. Count Islands With Total Value Divisible by K
Matrix Depth First Search
🐐🐐🐐🐐🐐
Medium
199. Binary Tree Right Side View
Breadth First SearchTree
🐐🐐🐐🐐🐐
Easy
206. Reverse Linked List
Linked List
🐐🐐🐐🐐🐐
Easy
270. Closest Binary Search Tree Value
Binary Search Tree
🐐🐐🐐🐐🐐
Medium
1324. Print Words Vertically
🐐🐐🐐🐐🐐
Easy
496. Next Greater Element I
Monostack
🐐🐐🐐🐐🐐
Medium
3212. Count Submatrices With Equal Frequency of X and Y
2D Prefix / Suffix
🐐🐐🐐🐐🐐
Medium
75. Sort Colors
Bucket Sort
🐐🐐🐐🐐🐐
Medium
1396. Design Underground System
🐐🐐🐐🐐🐐
Medium
1522. Diameter of N-Ary Tree
TreeTree Diameters
🐐🐐🐐🐐🐐
Medium
129. Sum Root to Leaf Numbers
TreeMath
🐐🐐🐐🐐🐐
Medium
515. Find Largest Value in Each Tree Row
Breadth First SearchTree
🐐🐐🐐🐐🐐
Easy
492. Construct the Rectangle
Number Theory
🐐🐐🐐🐐🐐
Medium
3904. Smallest Stable Index II
Prefix / Suffix
🐐🐐🐐🐐🐐
Medium
155. Min Stack
Stacks
🐐🐐🐐🐐🐐
Easy
111. Minimum Depth of Binary Tree
Breadth First SearchTree
🐐🐐🐐🐐🐐
Easy
144. Binary Tree Preorder Traversal
Tree
🐐🐐🐐🐐🐐
Easy
145. Binary Tree Postorder Traversal
Tree
🐐🐐🐐🐐🐐
Medium
200. Number of Islands
Matrix Depth First Search
🐐🐐🐐🐐🐐
Medium
15. 3Sum
Two Pointers
🐐🐐🐐🐐🐐
Medium
223. Rectangle Area
GeometryInclusion Exclusion
🐐🐐🐐🐐🐐
Medium
50. Pow(x, n)
Dynamic ProgrammingMath
🐐🐐🐐🐐🐐
Medium
49. Group Anagrams
Sliding Window - FixedHave Need Trick
🐐🐐🐐🐐🐐
Medium
1493. Longest Subarray of 1's After Deleting One Element
Sliding Window - Variable
🐐🐐🐐🐐🐐
Medium
2075. Decode the Slanted Ciphertext
🐐🐐🐐🐐🐐
Medium
923. 3Sum With Multiplicity
Prefix / Suffix
🐐🐐🐐🐐🐐
Medium
3895. Count Digit Appearances
🐐🐐🐐🐐🐐
Medium
102. Binary Tree Level Order Traversal
Breadth First SearchTree
🐐🐐🐐🐐🐐
Medium
167. Two Sum II - Input Array Is Sorted
Two Pointers
🐐🐐🐐🐐🐐
Medium
86. Partition List
Linked List
🐐🐐🐐🐐🐐
Easy
101. Symmetric Tree
Tree
🐐🐐🐐🐐🐐
Medium
82. Remove Duplicates from Sorted List II
Linked List
🐐🐐🐐🐐🐐
Medium
508. Most Frequent Subtree Sum
Tree
🐐🐐🐐🐐🐐
Medium
103. Binary Tree Zigzag Level Order Traversal
Breadth First SearchTree
🐐🐐🐐🐐🐐
Medium
56. Merge Intervals
🐐🐐🐐🐐🐐
Medium
1664. Ways to Make a Fair Array
Prefix / Suffix
🐐🐐🐐🐐🐐
Medium
62. Unique Paths
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
92. Reverse Linked List II
Linked List
🐐🐐🐐🐐🐐
Medium
3849. Maximum Bitwise XOR After Rearrangement
Bit Operations
🐐🐐🐐🐐🐐
Medium
77. Combinations
Backtracking
🐐🐐🐐🐐🐐
Medium
78. Subsets
Backtracking
🐐🐐🐐🐐🐐
Medium
848. Shifting Letters
Prefix / SuffixSweep Line
🐐🐐🐐🐐🐐
Medium
1031. Maximum Sum of Two Non-Overlapping Subarrays
Dynamic Programming State MachineSliding Window - FixedPrefix / Suffix
🐐🐐🐐🐐🐐
Medium
1020. Number of Enclaves
Matrix Depth First Search
🐐🐐🐐🐐🐐
Hard
778. Swim in Rising Water
DijkstraBinary Search on Answer
🐐🐐🐐🐐🐐
Medium
3290. Maximum Multiplication Score
Knapsack DP
🐐🐐🐐🐐🐐
Medium
2863. Maximum Length of Semi-Decreasing Subarrays
Binary SearchPrefix / Suffix
🐐🐐🐐🐐🐐
Medium
120. Triangle
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
1804. Implement Trie II (Prefix Tree)
Trie
🐐🐐🐐🐐🐐
Medium
3652. Best Time to Buy and Sell Stock using Strategy
Prefix / SuffixSliding Window - Fixed
🐐🐐🐐🐐🐐
Medium
3840. House Robber V
Knapsack DP
🐐🐐🐐🐐🐐
Medium
1325. Delete Leaves With a Given Value
Tree
🐐🐐🐐🐐🐐
Medium
3573. Best Time to Buy and Sell Stock V
Dynamic Programming State Machine
🐐🐐🐐🐐🐐
Medium
1008. Construct Binary Search Tree from Preorder Traversal
TreeRecursive ProblemsBinary Search Tree
🐐🐐🐐🐐🐐
Medium
3851. Maximum Requests Without Violating the Limit
Queue / DequeSliding Window - Variable
🐐🐐🐐🐐🐐
Medium
1504. Count Submatrices With All Ones
Rectangle DPDynamic ProgrammingMonostack
🐐🐐🐐🐐🐐
Hard
115. Distinct Subsequences
LCS DP
🐐🐐🐐🐐🐐
Medium
373. Find K Pairs with Smallest Sums
Heap
🐐🐐🐐🐐🐐
Medium
97. Interleaving String
Dynamic ProgrammingLCS DP
🐐🐐🐐🐐🐐
Medium
91. Decode Ways
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
2592. Maximize Greatness of an Array
Two Pointers
🐐🐐🐐🐐🐐
Medium
974. Subarray Sums Divisible by K
Lop Off Method
🐐🐐🐐🐐🐐
Medium
3868. Minimum Cost to Equalize Arrays Using Swaps
🐐🐐🐐🐐🐐
Medium
377. Combination Sum IV
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
962. Maximum Width Ramp
Binary SearchPrefix / SuffixMonostackTricky Sorting QuestionsTricky Two Pointers
🐐🐐🐐🐐🐐
Medium
1026. Maximum Difference Between Node and Ancestor
Tree
🐐🐐🐐🐐🐐
Medium
494. Target Sum
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
1155. Number of Dice Rolls With Target Sum
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
1801. Number of Orders in the Backlog
Heap
🐐🐐🐐🐐🐐
Hard
135. Candy
Constructive Algorithms
🐐🐐🐐🐐🐐
Medium
1053. Previous Permutation With One Swap
Constructive AlgorithmsPrefix / Suffix
🐐🐐🐐🐐🐐
Medium
935. Knight Dialer
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
3885. Design Event Manager
Sorted ContainersLazy Heap
🐐🐐🐐🐐🐐
Medium
2007. Find Original Array From Doubled Array
Constructive Algorithms
🐐🐐🐐🐐🐐
Medium
1914. Cyclically Rotating a Grid
Constructive Algorithms
🐐🐐🐐🐐🐐
Medium
447. Number of Boomerangs
Math
🐐🐐🐐🐐🐐
Medium
1156. Swap For Longest Repeated Character Substring
Dynamic ProgrammingSliding Window - Variable
🐐🐐🐐🐐🐐
Medium
2046. Sort Linked List Already Sorted Using Absolute Values
Linked List
🐐🐐🐐🐐🐐
Medium
1882. Process Tasks Using Servers
HeapSimulation
🐐🐐🐐🐐🐐
Medium
1943. Describe the Painting
Sweep Line
🐐🐐🐐🐐🐐
Hard
42. Trapping Rain Water
Prefix / SuffixTwo Pointers
🐐🐐🐐🐐🐐
Medium
3153. Sum of Digit Differences of All Pairs
HashmapCombinatorics
🐐🐐🐐🐐🐐
Medium
3761. Minimum Absolute Distance Between Mirror Pairs
Hashmap
🐐🐐🐐🐐🐐
Medium
18. 4Sum
Two Pointers
🐐🐐🐐🐐🐐
Medium
2074. Reverse Nodes in Even Length Groups
Linked List
🐐🐐🐐🐐🐐
Medium
998. Maximum Binary Tree II
Tree
🐐🐐🐐🐐🐐
Hard
132. Palindrome Partitioning II
Dynamic Programming
🐐🐐🐐🐐🐐
Medium
560. Subarray Sum Equals K
Lop Off Method
🐐🐐🐐🐐🐐
Medium
436. Find Right Interval
Binary Search
🐐🐐🐐🐐🐐
Medium
433. Minimum Genetic Mutation
Breadth First SearchGraphs
🐐🐐🐐🐐🐐
Medium
655. Print Binary Tree
Tree
🐐🐐🐐🐐🐐
Easy
169. Majority Element
Boyer Moore
🐐🐐🐐🐐🐐
Hard
140. Word Break II
Dynamic ProgrammingBacktracking
🐐🐐🐐🐐🐐
Easy
69. Sqrt(x)
Binary Search on Answer
🐐🐐🐐🐐🐐
Medium
128. Longest Consecutive Sequence
Probably just memorize this
🐐🐐🐐🐐🐐
Medium
131. Palindrome Partitioning
Backtracking
🐐🐐🐐🐐🐐
Medium
1277. Count Square Submatrices with All Ones
Rectangle DPDynamic Programming
🐐🐐🐐🐐🐐
Hard
381. Insert Delete GetRandom O(1) - Duplicates allowed
Swap and Pop Trick
🐐🐐🐐🐐🐐
Medium
1765. Map of Highest Peak
Multi-source Breadth First Search
🐐🐐🐐🐐🐐
Medium
721. Accounts Merge
Union Find
🐐🐐🐐🐐🐐
Hard
84. Largest Rectangle in Histogram
MonostackRectangle DP
🐐🐐🐐🐐🐐
Hard
2246. Longest Path With Different Adjacent Characters
Tree
🐐🐐🐐🐐🐐
Hard
1044. Longest Duplicate Substring
Binary Search on AnswerRolling HashSliding Window - Fixed
🐐🐐🐐🐐🐐
Hard
127. Word Ladder
Breadth First SearchGraphs
🐐🐐🐐🐐🐐
Medium
764. Largest Plus Sign
Dynamic Programming
🐐🐐🐐🐐🐐
Hard
1345. Jump Game IV
Breadth First Search
🐐🐐🐐🐐🐐
Hard
829. Consecutive Numbers Sum
Math
🐐🐐🐐🐐🐐
Medium
457. Circular Array Loop
Functional GraphsTortoise and Hare
🐐🐐🐐🐐🐐
Medium
307. Range Sum Query - Mutable
Square Root DecompSegment Tree
🐐🐐🐐🐐🐐
Hard
51. N-Queens
BacktrackingMath
🐐🐐🐐🐐🐐
Medium
1016. Binary String With Substrings Representing 1 To N
Bit OperationsSliding Window - Fixed
🐐🐐🐐🐐🐐
Medium
316. Remove Duplicate Letters
Monostack
🐐🐐🐐🐐🐐
Hard
710. Random Pick with Blacklist
Binary SearchProbably just memorize this
🐐🐐🐐🐐🐐
Medium
1722. Minimize Hamming Distance After Swap Operations
Graphs
🐐🐐🐐🐐🐐
Medium
1019. Next Greater Node In Linked List
Linked ListMonostack
🐐🐐🐐🐐🐐
Medium
71. Simplify Path
Stacks
🐐🐐🐐🐐🐐
Easy
203. Remove Linked List Elements
Linked List
🐐🐐🐐🐐🐐
Easy
110. Balanced Binary Tree
Tree
🐐🐐🐐🐐🐐
Medium
16. 3Sum Closest
Two Pointers
🐐🐐🐐🐐🐐
Medium
79. Word Search
Backtracking
🐐🐐🐐🐐🐐
Medium
380. Insert Delete GetRandom O(1)
Swap and Pop Trick
🐐🐐🐐🐐🐐
Medium
90. Subsets II
Backtracking
🐐🐐🐐🐐🐐
Medium
791. Custom Sort String
Bucket Sort
🐐 Goat Mode