--- title: "Day 01 - Advent of Code 2025" url: https://daily.dev/posts/day-01---advent-of-code-2025-pa69t9jxk source_url: https://www.youtube.com/watch?v=kHnuJyl3czA type: video:youtube source: "chris biscardi" published: 2026-05-31T07:48:52.437Z updated: 2026-05-31T09:16:22.607Z tags: ["rust"] reading_time: 44 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Day 01 - Advent of Code 2025 **[chris biscardi](https://daily.dev/sources/chrisbiscardi)** · 44 min read · 0 upvotes · 0 comments ## Summary A live coding walkthrough of Advent of Code 2025 Day 1 using Rust. The author sets up a Cargo workspace with a daily template, uses cargo-generate for scaffolding, and walks through solving both parts of the puzzle. Part 1 involves tracking how many times a rotating dial lands on zero; Part 2 counts zero crossings during rotations. The solution uses the nom parser combinator library to parse input into a typed Direction enum, rem_euclid for modular arithmetic, and rs_test for parameterized testing. The author also refactors the loop into a fold and discusses iterator tools like tuple_windows and cartesian_product. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#rust](https://daily.dev/tags/rust) [View this post on daily.dev](https://daily.dev/posts/day-01---advent-of-code-2025-pa69t9jxk)