📅 40-Day DSA Learning Schedule
Browse all days and see the primary + related problems for each pattern
You are currently on Day 25
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Hash Tables (Base)
Arrays & Hashing • Oct 23
🎯 Primary Problem
RequiredTwo Sum
Easy🎓 Master hash table lookups and complement pattern
🔗Solve on LeetCode💡 Related Problems
Same Pattern - Optional📚 Learning Resources
Hash Tables (Frequency Counter)
Arrays & Hashing • Oct 24
🎯 Primary Problem
RequiredSparse Arrays
Easy🎓 Master frequency counting with hash maps
🔗Solve on HackerRank💡 Related Problems
Same Pattern - OptionalTwo Pointers (Base)
Two Pointers • Oct 25
🎯 Primary Problem
RequiredValid Palindrome
Easy🎓 Master two pointer technique from both ends
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalTwo Pointers (Advanced)
Two Pointers • Oct 26
🎯 Primary Problem
RequiredTrapping Rain Water
Hard🎓 Master complex two pointer with height tracking
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalSliding Window (Fixed)
Sliding Window • Oct 27
🎯 Primary Problem
RequiredMax Subarray Sum (Fixed Size)
Easy🎓 Master fixed-size sliding window technique
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalBest Time to Buy and Sell Stock
💭 Single pass with tracking min/max - sliding window variant
Contains Duplicate II
💭 Sliding window with hash set for duplicates in range
Number of Sub-arrays of Size K
💭 Practice fixed window pattern
Sliding Window (Variable)
Sliding Window • Oct 28
🎯 Primary Problem
RequiredLongest Substring Without Repeating Characters
Medium🎓 Master variable-size sliding window with hash set
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalLongest Repeating Character Replacement
💭 Variable window + frequency counter
Minimum Window Substring
💭 Most complex sliding window problem
Permutation in String
💭 Fixed window with character frequency matching
Stack (Base)
Stack • Oct 29
🎯 Primary Problem
RequiredValid Parentheses
Easy🎓 Master stack for matching pairs pattern
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalBinary Search (Base)
Binary Search • Oct 30
🎯 Primary Problem
RequiredBinary Search
Easy🎓 Master iterative binary search template
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalBinary Search (Advanced)
Binary Search • Oct 31
🎯 Primary Problem
RequiredFind Minimum in Rotated Sorted Array
Medium🎓 Binary search on rotated arrays
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalLinked List (Base)
Linked List • Nov 1
🎯 Primary Problem
RequiredReverse Linked List
Easy🎓 Master linked list pointer manipulation
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalLinked List (Two Pointers)
Linked List • Nov 2
🎯 Primary Problem
RequiredRemove Nth Node From End
Medium🎓 Two pointer technique in linked lists
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalTrees (Traversal)
Trees • Nov 3
🎯 Primary Problem
RequiredBinary Tree Inorder Traversal
Easy🎓 Master tree traversal (iterative & recursive)
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalTrees (DFS)
Trees • Nov 4
🎯 Primary Problem
RequiredDiameter of Binary Tree
Easy🎓 DFS with return value pattern
🔗Solve on LeetCode💡 Related Problems
Same Pattern - OptionalTrees (BFS)
Trees • Nov 5
🎯 Primary Problem
RequiredBinary Tree Level Order Traversal
Medium🎓 Master BFS with queue for level-by-level traversal
🔗Solve on LeetCode💡 Related Problems
Same Pattern - Optional💡 How to Use This Schedule
- • Today: Focus on the current day (highlighted in purple)
- • Primary Problem: This is required to maintain your streak
- • Related Problems: Optional practice to master the pattern
- • Past Days: Green badges - you can still solve these for practice
- • Future Days: Gray badges - these unlock as you progress
- • Quick Nav: Use the day buttons at the bottom to jump to any day