DSA Notes

My handwritten-style study notes from the pattern-wise DSA playlists. Every page follows the same order: question → constraints → intuition → logic from examples → approach → Python code → line by line → dry run → complexity & remember.

• 1Binary Tree30 problems · DFS, BFS, views, paths, LCA, building trees
• 2Binary Search Tree15 problems · search, insert, delete, validate, iterator
• 3Binary Search22 videos · classic, rotated, bounds, matrices, search on answer
• 4Prefix Sum6 videos · 1D, prefix + hashmap, 2D
• 5Recursion8 videos · linear, branching, divide & conquer
• 6Stack25 videos · monotonic, undo, parentheses, expressions, design, greedy
• 7Sliding Window + Kadane17 videos · fixed, variable, counting windows, Kadane
• 8Linked List27 videos · fast/slow, reversal, merge/sort, dummy node, stack
• 9Two Pointers10 videos · opposite ends, same direction, expand around center

157 pages in total. Python only.