data structures & algorithms (foundations)
the 80% every engineer needs, from first principles. complexity, the memory hierarchy, the core structures, and the algorithms built on each. part 1 of 3.
17 lessons|5 modules|~3 hours
what you’ll learn
- reason about big-o, amortized cost, and why the memory hierarchy makes arrays fast
- build every core structure from scratch: dynamic arrays, hash tables, trees, heaps
- reach for two pointers, sliding window, and binary search without thinking
- implement merge, quick, and heap sort and know which one a real library reaches for
- traverse graphs with bfs and dfs, the patterns everything in part 2 builds on
curriculum
planning sketchthis is a rough curriculum we’re still planning. modules and lessons are likely to shift before any lesson is recorded. want to shape it? mail@karnstack.com.
01
module one
the cost of everything
41 min4 lessons01complexity: big-o, amortized, and the cost model that matterscoming soon11m
02the memory hierarchy: why arrays are fastcoming soon13m
03arrays and dynamic arrays from scratchcoming soon10m
04strings: immutability, builders, and the hidden o(n)coming soon7m
checkpoint
module quiz · the cost of everything
5 questions · ~5m · test your recall before moving on
02
module two
linear structures and their patterns
43 min4 lessons05linked lists: when they actually beat arrayscoming soon10m
06stacks and queues: the workhorsescoming soon9m
07two pointers and sliding windowcoming soon11m
08binary search: one template for every variantcoming soon13m
checkpoint
module quiz · linear structures and their patterns
5 questions · ~5m · test your recall before moving on
03
module three
recursion and sorting
33 min3 lessons09thinking recursively: the call stack made concretecoming soon10m
10comparison sorts: merge, quick, heap, and how libraries sortcoming soon14m
11divide and conquercoming soon9m
checkpoint
module quiz · recursion and sorting
5 questions · ~5m · test your recall before moving on
04
module four
hashing and trees
42 min4 lessons12hash tables: collisions, load factor, and resizingcoming soon13m
13binary trees and the four traversalscoming soon10m
14binary search trees and the degenerate casecoming soon9m
15heaps and priority queuescoming soon10m
checkpoint
module quiz · hashing and trees
5 questions · ~5m · test your recall before moving on
05
module five
first steps into graphs
21 min2 lessons16representing graphs: adjacency list vs matrixcoming soon8m
17bfs and dfs: the traversal patterns everything builds oncoming soon13m
checkpoint
module quiz · first steps into graphs
5 questions · ~5m · test your recall before moving on
frequently asked
- when does this launch?
- in planning. the curriculum on this page is a sketch. modules and lessons are likely to shift before any lesson is recorded. every plan includes every course as it ships.
- is this just leetcode prep?
- interview readiness is a side effect, not the goal. each structure is taught with the production system it powers, so you understand why it exists, not just how to pass a test.
- what language is the code in?
- lessons teach with pseudocode and diagrams so the idea stays language-agnostic. the written companion below each video carries full typescript, go, and c++ implementations.