commit fe2df25079b05f832b4f71b1808f3b4ac2b9fc0e · kokirigla.de/aoc2025

+98

src/day2.rs

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       use anyhow::Context;

     

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       const INPUT: &str = include_str!("input/2/actual.txt");

     

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       const IS_PART_2: bool = true;

     

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       pub fn main() -> anyhow::Result<()> {

     

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           let ranges = parse(INPUT).context("parsing input")?;

     

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           let mut sum: u128 = 0;

     

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           for range in &ranges {

     

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               let range_sum = range

     

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                   .sum_of_invalid_ids()

     

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                   .context("summing invalid IDs for range")?;

     

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               sum += range_sum;

     

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           }

     

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           println!("TOTAL SUM OF INVALID NUMBERS IS {}", sum);

     

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           Ok(())

     

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       }

     

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       struct Range(u128, u128);

     

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       impl Range {

     

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           pub fn sum_of_invalid_ids(&self) -> anyhow::Result<u128> {

     

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               let mut sum: u128 = 0;

     

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               for n in self.0..=self.1 {

     

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                   if (if IS_PART_2 {

     

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                       is_invalid_pt_2(n)

     

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                   } else {

     

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                       is_invalid(n)

     

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                   })

     

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                   .context("checking invalidity")?

     

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                   {

     

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                       // println!("{} is invalid", n);

     

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                       sum += n

     

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                   } else {

     

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                       // println!("{} is valid", n);

     

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                   }

     

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               }

     

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               Ok(sum)

     

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           }

     

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       }

     

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       fn parse(input: &str) -> anyhow::Result<Vec<Range>> {

     

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           let input = input.trim();

     

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           let mut ranges = Vec::new();

     

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           input

     

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               .split(',')

     

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               .try_for_each(|raw_range| -> anyhow::Result<()> {

     

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                   let split_raw = raw_range.split('-').collect::<Vec<&str>>();

     

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                   let first = split_raw

     

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                       .get(0)

     

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                       .context("getting first")?

     

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                       .parse::<u128>()

     

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                       .context("parsing first")?;

     

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                   let second = split_raw

     

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                       .get(1)

     

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                       .context("getting second")?

     

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                       .parse::<u128>()

     

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                       .context("parsing second")?;

     

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                   ranges.push(Range(first, second));

     

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                   Ok(())

     

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               })

     

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               .context("running loop")?;

     

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           Ok(ranges)

     

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       }

     

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       fn is_invalid_pt_2(num: u128) -> anyhow::Result<bool> {

     

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           let as_string = num.to_string();

     

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           let length = as_string.len();

     

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           for i in 1..=length / 2 {

     

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               if length % i != 0 {

     

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                   continue;

     

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               }

     

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               let pattern = &as_string[0..i];

     

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               let repetitions = length / i;

     

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               if pattern.repeat(repetitions) == as_string {

     

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                   return Ok(true);

     

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               }

     

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           }

     

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           Ok(false)

     

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       }

     

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       fn is_invalid(num: u128) -> anyhow::Result<bool> {

     

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           let as_string = num.to_string();

     

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           let middle = as_string.len() / 2;

     

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           let split = as_string.split_at(middle);

     

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           let (left, right) = (split.0.to_string(), split.1.to_string());

     

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           Ok(left == right)

     

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       }

src/input/2/actual.txt

···

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       92916254-92945956,5454498003-5454580069,28-45,4615-7998,4747396917-4747534264,272993-389376,36290651-36423050,177-310,3246326-3418616,48-93,894714-949755,952007-1003147,3-16,632-1029,420-581,585519115-585673174,1041-1698,27443-39304,71589003-71823870,97-142,2790995-2837912,579556301-579617006,653443-674678,1515120817-1515176202,13504-20701,1896-3566,8359-13220,51924-98061,505196-638209,67070129-67263432,694648-751703,8892865662-8892912125

src/input/2/example.txt

···

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···

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       11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124

src/main.rs

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       use anyhow::Context;

     

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       mod day1;

     

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       fn main() -> anyhow::Result<()> {

     

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           println!("day 1...");

     

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           day1::main().context("running day 1")?;

     

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           Ok(())

     

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       }

···

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       use anyhow::Context;

     

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       mod day1;

     

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       mod day2;

     

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       fn main() -> anyhow::Result<()> {

     

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           println!("day 1...");

     

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           day1::main().context("running day 1")?;

     

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           println!("day 2...");

     

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           day2::main().context("running day2")?;

     

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           Ok(())

     

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       }