Function aoc::y23d03::y23d03p1

pub fn y23d03p1(input: &str) -> u32

The solution for part one of the day three challenge.

Given the problem input as a string we start by building a grid representation of each character into a std::collections::HashMap then we loop through our grid line by line and character by character. We keep track if we’ve found a number and then when we either stop seeing numbers or we get to the end of the line we check to see if what we’ve found is adjacent to any of the symbols present in the grid and if it is then we add it to the final sum.

Example

// probably read this from the input file...
let input = "123.\n.*..\n....\n.456";
assert_eq!(y23d03p1(input), 123);