Advent of Code

sneak peek

Netflix adaptation ;)

1. Quick hacking in browser console
2. Same + regex
3. First graph
4. TDD and it worked 😱

                    describe('iterator', () => {
                      it('moves to next state - easy scenario', () => {
                        // given
                        const toTest = iterator(
                          `Card 172: 92  9 73 82 15  6 44 28 88 34 | 99 78 11 46  9 36 89 65 17  8 16 94 68 63 12 54 25 33 69 47 13 38 93 50 59
                          Card 173: 31 18 13 56 72 | 74 77 10 23 35 67 36 11`);

                        expect(toTest.state).toEqual(new Map([[172, 1], [173, 1]]));

                        // when
                        toTest.next();

                        // then
                        expect(toTest.state).toEqual(new Map([[172, 1], [173, 2]]));
                        expect(toTest.hasNext()).toBe(true);
                

1. Quick hacking in browser console
2. Same + regex
3. First graph
4. TDD and it worked 😱
5. First issues
   • Map? OOM
   • Brute force? 18m

<v p:0*2a;=list size;                     n(4"FRTH"(4"TOYS"                                         ;;
         ;stack = [next values] [current values] dst_range src_range ln i;                          ;;
         ;depth =      (n+4)+   (n+4-1) - 4      3         2         1  0;

 >          gk& 00g 01p v
                >$ a, & v;read line;    ;Vi<src?;      ;Vi>ln?; ;Ni=dst+(Vi-src),size-=1;
   >                    >&& 01g:!#v  _  :3+P 3P- :0\`!] :3P \`] 4P+ 01g4+0\-L :3+L$ 01g1-01p   v
    >$ 0g:01p :!|!:-1 <              !                |       |
   $^;reset; <  > :P. ^              :          ;i--; $       $
   |`\0: -0'_^# `a: ~v#< 0    $k3 <  ^             -1 <       <                                <
    ;\n\n = new map; >$                                                                        v
   > \a*+              ^                                             @,a.,a  N $$(4"IMTH"  D   <
    ;we have to read the first number;
    ;of a new group by hand because  ;
    ;we cant detect line breaks      ;
                

1. Python
2. Rust
3. C#, JS/TS, Kotlin, Java

• Zig
• D
• APL
• Vim keystrokes

1. Quick hacking in browser console
2. Same + regex
3. First graph
4. TDD and it worked 😱
5. First issues

Day 8

                    describe('parseInstructions', () => {
                        it('loops through instructions till needed', () => {
                            const first = parseInstructions('RL');
                            const second = parseInstructions('LLR');

                            expect(first.next().value).toEqual(1);
                            expect(second.next().value).toEqual(0);

                            expect(first.next().value).toEqual(0);
                            expect(second.next().value).toEqual(0);
                

                    export function* parseInstructions(input) {
                        const instructions = input.split('');
                        const dictionary = {
                            'L': 0,
                            'R': 1
                        };
                        for (let index = 0; ; index++) {
                            yield dictionary[instructions[index % instructions.length]];
                        }
                    }
                

+Least Common Multiple, +GCD

Day 10

                    const resizedTimes3 = new Map([
                        ['J', [
                            '.|.',
                            '-J.',
                            '...',
                        ]]
                

Day 11

Day 12

                    console.time();
                    console.log(countAllArrangements(`input here`));
                    console.timeEnd();
                

Day 13

                    function transpose(arr) {
                        return arr[0].map((_, i) => arr.map(row => row[i]));
                    }
                

Day 14

• transpose!
• Array of stack of results

15. EZ! Map preserves the order
16. Performant? DP? Premature optimization
17. Good abstractions = smooth 2nd part
18. Pick's theorem, Shoelace formula

Day 19

                    export function parsePart(input) {
                        return eval(`(function() { return ${input}; })()`.replaceAll('=', ':'));
                    }
                

Day 20

1. Redux/Flux, bez TDD
2. Got from HyperNeutrino
   • Input data analysis
   • Graphviz, looking for cycles

Day 21

• Misleading example
• Even more input data analysis

Day 22

Day 23

Day 24

1. Maths - crossing points
2. Z3 👎🏻

Day 25