Source: https://mokxi.com/teachers/plans/data-structures-algorithms Updated: 2026-11-11 Lesson plan # Data structures and algorithms lesson plan The ideas every programmer is asked about, built and measured on an Uno: big O, linked lists, stacks and queues, hash maps, sorting and binary search. Ends with a leaderboard that needs them all. 4 chapters, 7 lessons, about 6 hours, on the Arduino Uno R3. Every lesson runs in the browser, with nothing to install. Start a class from this course The unit ## Objectives and materials ### By the end, students can - Arrays, big O, and lists made from a fixed pool of nodes. - Stacks, queues and a hash map: limits that make things fast. - Three sorts raced and counted, then binary search and its off-by-one. - A leaderboard for a reaction game, built from the whole course. ### Materials for the whole unit - Arduino Uno R3 - Full-size breadboard - LED x 3 - Pushbutton - Resistor x 3 Every part is already on the simulator’s bench, so there is nothing to buy or hand out. The counts are the most any one lesson uses, if you build it on real breadboards too. Chapter 1. About 1 h 40 min ## What things cost Arrays, big O, and lists made from a fixed pool of nodes. Lesson | Time | What students do Arrays and big O One block of 64 ints: an index lookup that costs one step, a scan that costs up to n, a pair check that costs n squared over two, and a table that shows each cost as n doubles. | 50 min - Run it: 64 ints in a row - An index lookup is O(1) - Finding a value is O(n) - The worst case - Count the work as n doubles - O(n^2): every pair - Double n yourself Linked lists Nodes joined by pointers, taken from a fixed pool of 16 so nothing can fragment: add at the head, insert and delete in the middle, run the pool dry, and fix a reverse that leaks. | 50 min - Run it: a pool of nodes - Add at the head: O(1) - Insert in the middle - Delete, and the pointer to a pointer - Run the pool dry - Reverse it, and watch it vanish - Fix the reverse ### Materials - Arduino Uno R3 - Full-size breadboard - LED x 3 - Pushbutton - Resistor x 3 ### Check for understanding Each student finishes "Linked lists" on their own, without opening the hints. The simulator checks 7 of its 7 steps as they go. Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Fix the reverse". Chapter 2. About 1 h 35 min ## Structures with rules Stacks, queues and a hash map: limits that make things fast. Lesson | Time | What students do Stacks and queues An array stack that matches brackets and undoes a running total, and a ring-buffer queue of lamp tasks fed by the serial monitor and the button. Then a stack that overflows, and the fix. | 50 min - Run it: two shapes - Match brackets with a stack - Catch a mismatch - Undo is a stack - A queue of tasks - A full queue says no - Stack overflow Hash maps An 8 slot open-addressing table: a hash function turns a name into a home slot, collisions probe onward, tombstones keep chains whole, the load factor lights a lamp, and a better hash spreads the names out. | 45 min - Run it: names to slots - Set and get in one probe - A collision - The load factor - Delete with a tombstone - A better hash ### Materials - Arduino Uno R3 - Full-size breadboard - LED x 3 - Pushbutton - Resistor x 3 ### Check for understanding Each student finishes "Hash maps" on their own, without opening the hints. The simulator checks 6 of its 6 steps as they go. Then ask each one to explain, in a sentence or two, the last thing it asked of them: "A better hash". Chapter 3. About 1 h 40 min ## Put it in order, find it fast Three sorts raced and counted, then binary search and its off-by-one. Lesson | Time | What students do Sorting Bubble, insertion and quick sort on the same 16 numbers with every comparison and swap counted, best and worst cases, stability shown with tags, a race to 64, and an early exit that makes bubble sort smart. | 50 min - Run it: 16 numbers - Bubble sort - Insertion sort - Quick sort, and its bad day - Stability - Race them as n doubles - Teach bubble sort to stop Searching and binary search Linear against binary search on 100 sorted numbers with comparisons counted, a slow-motion search on the lamps, a guessing game in ten tries, and an off-by-one found by a self-test. | 50 min - Run it: 100 sorted values - Linear: 51 looks - Binary: 6 looks - Watch it on the lamps - Play: I guess your number - A self-test finds an off-by-one - Fix the off-by-one ### Materials - Arduino Uno R3 - Full-size breadboard - LED x 3 - Pushbutton - Resistor x 3 ### Check for understanding Each student finishes "Searching and binary search" on their own, without opening the hints. The simulator checks 7 of its 7 steps as they go. Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Fix the off-by-one". Chapter 4. About 1 h ## Boss A leaderboard for a reaction game, built from the whole course. Lesson | Time | What students do Boss: a leaderboard A reaction game and its leaderboard built from the course: players in a hash map, a ranking kept sorted by one insertion pass, binary search for where a score would land, and a stable rule for ties. | 60 min - Run it: the board is open - Submit scores - Look up by name - A new best moves up - Where would 500 rank? - Play: the button game - Make ties fair - Make it yours ### Materials - Arduino Uno R3 - Full-size breadboard - LED x 3 - Pushbutton - Resistor x 3 ### Check for understanding Each student finishes "Boss: a leaderboard" on their own, without opening the hints. The simulator checks 8 of its 8 steps as they go. Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Make it yours". Your class ## Teach this unit as a class Start a class from this course and its 7 lessons are assigned in one go, in order. Students join with a six-character code or printed login cards, and each one’s work comes back to you. The class tools are free for 30 days for one class of up to 20 students, with no card. The lessons themselves are free either way. Start a class from this course See the demo class More units ## Other lesson plans Electronics basics 20 lessons, about 10 h. Embedded on the Arduino Uno 16 lessons, about 12 h. Embedded on the ESP32-C3 13 lessons, about 11 h. Embedded on the Raspberry Pi Pico 7 lessons, about 6 h. Build your own fight stick 5 lessons, about 4 h. Embedded on the STM32F411 6 lessons, about 6 h. C++ on a board 13 lessons, about 10 h. Digital logic and memory 4 lessons, about 4 h. Interactive devices on the Uno 9 lessons, about 8 h. From gates to a computer 23 lessons, about 16 h. Build a claw machine 8 lessons, about 6 h. Every unit All the courses as ready-made units, on the teachers page.