DSA

58 boards, 70 lessons, 546 review questions and 23 narrated videos, in 10 chapters. Read them in order. Each chapter builds on the one before.

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Start here → Complexity & Big-O

WatchDSA, end to end22 All 23 videos →

Contents

Part one · Foundations

1The toolbox7 lessons
The judge for speed, then the structures everything else is built from: arrays, hash maps, lists and stacks, trees, graphs, sorting and searching.
▶ Watch the video
Complexity and Big-O Arrays and Strings Hashing Linked Lists Stacks and Queues Trees Graphs Sorting and Searching
2Choosing the attack5 lessons
Recursion and DP, the four design families, a capstone on a problem you have never seen, and the shapes interview problems come in.
after The toolbox
Recursion and Dynamic Programming Algorithm Design Patterns Capstone Attack an Unseen Problem Pattern Recognition
3Worked, and deeper9 lessons
The DP table filled by hand, shortest paths traced, string search, balanced and range trees, problems that are provably hard, and thinking in bits.
after Choosing the attack
The DP Table Shortest Path Traced Finding the Needle Rotations and Range Trees When Problems Are Hard Thinking in Bits
4DSA, in Hinglish10 lessons
The same complexity-to-DP arc as the DSA track, retold in Hinglish for a reader who thinks better in it.
Complexity, Big-O Ka Poora Naksha Recursion, Memo, Table, DP Engine Arrays, Do-Pointer, Window Hashing, O(1) Yaad Sorting aur Searching Stacks aur Queues Linked Lists aur Pointers Trees aur Recursion Graphs Dynamic Programming

Part two · Build

5Clinic: arrays, hashing and stacks7 lessons
Seven named interview problems worked in Hinglish: Two Sum, the sliding window, two pointers, reversing a list, and the stack and its monotonic cousin.
after The toolbox
Two Sum Longest Substring Without Repeating Container With Most Water 3Sum Reverse a Linked List Valid Parentheses Daily Temperatures
6Clinic: search, trees, graphs and heaps9 lessons
Nine problems worked in Hinglish: binary search twice, two tree recursions, islands and course schedule, the top-k pair, and meeting rooms.
after The toolbox
Binary Search Search in Rotated Sorted Array Maximum Depth of Binary Tree Diameter of Binary Tree Number of Islands Course Schedule Kth Largest Element Top K Frequent Elements Meeting Rooms II
7Clinic: recursion, backtracking and DP6 lessons
Six problems worked in Hinglish: subsets and combination sum, then Climbing Stairs to Longest Common Subsequence, one-dimensional DP into two.
after The toolbox
Subsets Combination Sum Climbing Stairs Coin Change Unique Paths Longest Common Subsequence
8Worked problems, in English13 lessons
Twelve more named problems, in English: tries, Dijkstra, union-find, greedy, intervals, matrices, fast power, XOR, binary search on the answer, and Floyd's cycle.
after The toolbox
9Built from the toolbox3 lessons
Two real tools built from lessons you already have: a line diff, first as the DP table and then as the greedy walk git uses, and an autocomplete that answers every keystroke from a trie.
after Choosing the attack

Part three · Depth

10Git Diff1 lesson
Why `git diff` is fast: the DP table that dies at scale, the edit graph it's really solving, and the Myers greedy BFS that git actually ships.
after The toolboxGit Diff case study →
- 01Git's diff (Myers' algorithm), the case study15 Q
The Map Two Files, One Question The DP Table and Why It Dies The Edit Graph Myers Greedy BFS Reading the Trace Back Linear Space What Git Actually Ships Everything

Borrowed from other tracks (3)

You don't need to take those tracks. These are the only lessons this track uses from them, and each is linked where it is needed.