Generally, I start each problem defining the domain models which capture all the information provided via the input. Then, once I've completed parsing into that data structure, I'll solve the problem.
I prefer functional/immutable data-oriented approaches over dynamic ones.
Use commands like the following to run and experiment with the TypeScript solutions. If you don't have deno, you can follow the installation instructions.
deno run -A --watch ./part-1.ts
deno run -A --watch ./part-2.ts