My submissions for Advent of Code 2025
adventofcode.com/2025
cherry.computer
rust
aoc
add solution for day 8 part 1
+4
08/part1/Cargo.toml
+4
08/part1/Cargo.toml
+55
08/part1/src/main.rs
+55
08/part1/src/main.rs
···
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use std::{collections::HashSet, fs::read_to_string};
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fn main() {
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let boxes: Vec<Vec<u64>> = read_to_string("../input.txt")
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.expect("failed to open input file")
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.lines()
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.map(|jbox| {
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jbox.split(',')
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.map(|coord| coord.parse().unwrap())
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.collect()
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})
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.collect();
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let mut distances: Vec<(_, u64)> = boxes
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.iter()
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.enumerate()
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.flat_map(|(i, jbox)| {
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boxes.iter().enumerate().skip(i + 1).map(move |(j, other)| {
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(
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(i, j),
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jbox.iter()
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.zip(other)
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.map(|(from, to)| from.abs_diff(*to).pow(2))
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.sum(),
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)
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})
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})
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.collect();
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distances.sort_unstable_by_key(|(_, distance)| *distance);
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let mut circuits: Vec<HashSet<usize>> = Vec::new();
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for ((from, to), _) in distances.into_iter().take(1000) {
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let from_idx = circuits.iter().position(|circuit| circuit.contains(&from));
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let to_idx = circuits.iter().position(|circuit| circuit.contains(&to));
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match (from_idx, to_idx) {
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(Some(from_idx), Some(to_idx)) if from_idx == to_idx => {}
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(Some(from_idx), Some(to_idx)) => {
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let to_circuit: Vec<_> = circuits[to_idx].drain().collect();
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circuits[from_idx].extend(to_circuit);
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circuits.remove(to_idx);
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}
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(Some(from_idx), None) => {
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circuits[from_idx].insert(to);
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}
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(None, Some(to_idx)) => {
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circuits[to_idx].insert(from);
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}
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(None, None) => circuits.push(HashSet::from([from, to])),
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}
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}
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let mut circuit_sizes: Vec<_> = circuits.into_iter().map(|circuit| circuit.len()).collect();
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circuit_sizes.sort_unstable();
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let result: usize = circuit_sizes.into_iter().rev().take(3).product();
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println!("The result of multiplying the size of the three largest circuits is {result}!");
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}