NeetCode 150 — LeetCode Study Plan

The NeetCode 150 expands the Blind 75 to 150 problems covering every pattern coding interviews test. Here is the full list, grouped by category. Problems with a link have a full write-up — key idea, solution, and a step-by-step visualization — and every one is built to review with spaced repetition so the pattern sticks.

We have 150 of these with full solutions.

Arrays & Hashing

• Contains DuplicateEASY
• Valid AnagramEASY
• Two SumEASY
• Group AnagramsMEDIUM
• Top K Frequent ElementsMEDIUM
• Encode and Decode StringsMEDIUM
• Product of Array Except SelfMEDIUM
• Valid SudokuMEDIUM
• Longest Consecutive SequenceMEDIUM

Two Pointers

• Valid PalindromeEASY
• Two Sum II - Input Array Is SortedMEDIUM
• 3SumMEDIUM
• Container With Most WaterMEDIUM
• Trapping Rain WaterHARD

Sliding Window

• Best Time to Buy and Sell StockEASY
• Longest Substring Without Repeating CharactersMEDIUM
• Longest Repeating Character ReplacementMEDIUM
• Permutation in StringMEDIUM
• Minimum Window SubstringHARD
• Sliding Window MaximumHARD

Stack

• Valid ParenthesesEASY
• Min StackMEDIUM
• Evaluate Reverse Polish NotationMEDIUM
• Generate ParenthesesMEDIUM
• Daily TemperaturesMEDIUM
• Car FleetMEDIUM
• Largest Rectangle in HistogramHARD

Binary Search

• Binary SearchEASY
• Search a 2D MatrixMEDIUM
• Koko Eating BananasMEDIUM
• Find Minimum in Rotated Sorted ArrayMEDIUM
• Search in Rotated Sorted ArrayMEDIUM
• Time Based Key-Value StoreMEDIUM
• Median of Two Sorted ArraysHARD

Linked List

• Reverse Linked ListEASY
• Merge Two Sorted ListsEASY
• Reorder ListMEDIUM
• Remove Nth Node From End of ListMEDIUM
• Copy List with Random PointerMEDIUM
• Add Two NumbersMEDIUM
• Linked List CycleEASY
• Find the Duplicate NumberMEDIUM
• LRU CacheMEDIUM
• Merge k Sorted ListsHARD
• Reverse Nodes in k-GroupHARD

Trees

• Invert Binary TreeEASY
• Maximum Depth of Binary TreeEASY
• Diameter of Binary TreeEASY
• Balanced Binary TreeEASY
• Same TreeEASY
• Subtree of Another TreeEASY
• Lowest Common Ancestor of a Binary Search TreeMEDIUM
• Binary Tree Level Order TraversalMEDIUM
• Binary Tree Right Side ViewMEDIUM
• Count Good Nodes in Binary TreeMEDIUM
• Validate Binary Search TreeMEDIUM
• Kth Smallest Element in a BSTMEDIUM
• Construct Binary Tree from Preorder and Inorder TraversalMEDIUM
• Binary Tree Maximum Path SumHARD
• Serialize and Deserialize Binary TreeHARD

Tries

• Implement Trie (Prefix Tree)MEDIUM
• Design Add and Search Words Data StructureMEDIUM
• Word Search IIHARD

Heap / Priority Queue

• Kth Largest Element in a StreamEASY
• Last Stone WeightEASY
• K Closest Points to OriginMEDIUM
• Kth Largest Element in an ArrayMEDIUM
• Task SchedulerMEDIUM
• Design TwitterMEDIUM
• Find Median from Data StreamHARD

Backtracking

• SubsetsMEDIUM
• Combination SumMEDIUM
• PermutationsMEDIUM
• Subsets IIMEDIUM
• Combination Sum IIMEDIUM
• Word SearchMEDIUM
• Palindrome PartitioningMEDIUM
• Letter Combinations of a Phone NumberMEDIUM
• N-QueensHARD

Graphs

• Number of IslandsMEDIUM
• Max Area of IslandMEDIUM
• Clone GraphMEDIUM
• Walls and GatesMEDIUM
• Rotting OrangesMEDIUM
• Pacific Atlantic Water FlowMEDIUM
• Surrounded RegionsMEDIUM
• Course ScheduleMEDIUM
• Course Schedule IIMEDIUM
• Graph Valid TreeMEDIUM
• Number of Connected Components in an Undirected GraphMEDIUM
• Redundant ConnectionMEDIUM
• Word LadderHARD

Advanced Graphs

• Reconstruct ItineraryHARD
• Min Cost to Connect All PointsMEDIUM
• Network Delay TimeMEDIUM
• Swim in Rising WaterHARD
• Alien DictionaryHARD
• Cheapest Flights Within K StopsMEDIUM

1-D DP

• Climbing StairsEASY
• Min Cost Climbing StairsEASY
• House RobberMEDIUM
• House Robber IIMEDIUM
• Longest Palindromic SubstringMEDIUM
• Palindromic SubstringsMEDIUM
• Decode WaysMEDIUM
• Coin ChangeMEDIUM
• Maximum Product SubarrayMEDIUM
• Word BreakMEDIUM
• Longest Increasing SubsequenceMEDIUM
• Partition Equal Subset SumMEDIUM

2-D DP

• Unique PathsMEDIUM
• Longest Common SubsequenceMEDIUM
• Best Time to Buy and Sell Stock with CooldownMEDIUM
• Coin Change IIMEDIUM
• Target SumMEDIUM
• Interleaving StringMEDIUM
• Longest Increasing Path in a MatrixHARD
• Distinct SubsequencesHARD
• Edit DistanceHARD
• Burst BalloonsHARD
• Regular Expression MatchingHARD

Greedy

• Maximum SubarrayMEDIUM
• Jump GameMEDIUM
• Jump Game IIMEDIUM
• Gas StationMEDIUM
• Hand of StraightsMEDIUM
• Merge Triplets to Form Target TripletMEDIUM
• Partition LabelsMEDIUM
• Valid Parenthesis StringMEDIUM

Intervals

• Insert IntervalMEDIUM
• Merge IntervalsMEDIUM
• Non-overlapping IntervalsMEDIUM
• Meeting RoomsEASY
• Meeting Rooms IIMEDIUM
• Minimum Interval to Include Each QueryHARD

Math & Geometry

• Rotate ImageMEDIUM
• Spiral MatrixMEDIUM
• Set Matrix ZeroesMEDIUM
• Happy NumberEASY
• Plus OneEASY
• Multiply StringsMEDIUM
• Detect SquaresMEDIUM
• Pow(x, n)MEDIUM

Bit Manipulation

• Single NumberEASY
• Number of 1 BitsEASY
• Counting BitsEASY
• Reverse BitsEASY
• Missing NumberEASY
• Sum of Two IntegersMEDIUM
• Reverse IntegerMEDIUM