Blind 75 — LeetCode Study Plan

The Blind 75 is the classic shortlist of LeetCode problems that cover the patterns most 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 75 of these with full solutions.

Array

• Two SumEASY
• Best Time to Buy and Sell StockEASY
• Contains DuplicateEASY
• Product of Array Except SelfMEDIUM
• Maximum SubarrayMEDIUM
• Maximum Product SubarrayMEDIUM
• Find Minimum in Rotated Sorted ArrayMEDIUM
• Search in Rotated Sorted ArrayMEDIUM
• 3SumMEDIUM
• Container With Most WaterMEDIUM

Binary

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

Dynamic Programming

• Climbing StairsEASY
• Coin ChangeMEDIUM
• Longest Increasing SubsequenceMEDIUM
• Longest Common SubsequenceMEDIUM
• Word BreakMEDIUM
• Combination SumMEDIUM
• House RobberMEDIUM
• House Robber IIMEDIUM
• Decode WaysMEDIUM
• Unique PathsMEDIUM
• Jump GameMEDIUM

Graph

• Clone GraphMEDIUM
• Course ScheduleMEDIUM
• Pacific Atlantic Water FlowMEDIUM
• Number of IslandsMEDIUM
• Longest Consecutive SequenceMEDIUM
• Alien DictionaryHARD
• Graph Valid TreeMEDIUM
• Number of Connected Components in an Undirected GraphMEDIUM

Interval

• Insert IntervalMEDIUM
• Merge IntervalsMEDIUM
• Non-overlapping IntervalsMEDIUM
• Meeting RoomsEASY
• Meeting Rooms IIMEDIUM

Linked List

• Reverse Linked ListEASY
• Linked List CycleEASY
• Merge Two Sorted ListsEASY
• Merge k Sorted ListsHARD
• Remove Nth Node From End of ListMEDIUM
• Reorder ListMEDIUM

Matrix

• Set Matrix ZeroesMEDIUM
• Spiral MatrixMEDIUM
• Rotate ImageMEDIUM
• Word SearchMEDIUM

String

• Longest Substring Without Repeating CharactersMEDIUM
• Longest Repeating Character ReplacementMEDIUM
• Minimum Window SubstringHARD
• Valid AnagramEASY
• Group AnagramsMEDIUM
• Valid ParenthesesEASY
• Valid PalindromeEASY
• Longest Palindromic SubstringMEDIUM
• Palindromic SubstringsMEDIUM
• Encode and Decode StringsMEDIUM

Tree

• Maximum Depth of Binary TreeEASY
• Same TreeEASY
• Invert Binary TreeEASY
• Binary Tree Maximum Path SumHARD
• Binary Tree Level Order TraversalMEDIUM
• Serialize and Deserialize Binary TreeHARD
• Subtree of Another TreeEASY
• Construct Binary Tree from Preorder and Inorder TraversalMEDIUM
• Validate Binary Search TreeMEDIUM
• Kth Smallest Element in a BSTMEDIUM
• Lowest Common Ancestor of a Binary Search TreeMEDIUM
• Implement Trie (Prefix Tree)MEDIUM
• Design Add and Search Words Data StructureMEDIUM
• Word Search IIHARD

Heap / Priority Queue

• Top K Frequent ElementsMEDIUM
• Find Median from Data StreamHARD