commit fe2df25079b05f832b4f71b1808f3b4ac2b9fc0e · kokirigla.de/aoc2025

+98

src/day2.rs

···

       1
       1
       +
       use anyhow::Context;

     

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

     

       3
       3
       +
       const IS_PART_2: bool = true;

     

       4
       4
       +
       

     

       5
       5
       +
       pub fn main() -> anyhow::Result<()> {

     

       6
       6
       +
           let ranges = parse(INPUT).context("parsing input")?;

     

       7
       7
       +
       

     

       8
       8
       +
           let mut sum: u128 = 0;

     

       9
       9
       +
       

     

       10
       10
       +
           for range in &ranges {

     

       11
       11
       +
               let range_sum = range

     

       12
       12
       +
                   .sum_of_invalid_ids()

     

       13
       13
       +
                   .context("summing invalid IDs for range")?;

     

       14
       14
       +
               sum += range_sum;

     

       15
       15
       +
           }

     

       16
       16
       +
       

     

       17
       17
       +
           println!("TOTAL SUM OF INVALID NUMBERS IS {}", sum);

     

       18
       18
       +
       

     

       19
       19
       +
           Ok(())

     

       20
       20
       +
       }

     

       21
       21
       +
       

     

       22
       22
       +
       struct Range(u128, u128);

     

       23
       23
       +
       

     

       24
       24
       +
       impl Range {

     

       25
       25
       +
           pub fn sum_of_invalid_ids(&self) -> anyhow::Result<u128> {

     

       26
       26
       +
               let mut sum: u128 = 0;

     

       27
       27
       +
               for n in self.0..=self.1 {

     

       28
       28
       +
                   if (if IS_PART_2 {

     

       29
       29
       +
                       is_invalid_pt_2(n)

     

       30
       30
       +
                   } else {

     

       31
       31
       +
                       is_invalid(n)

     

       32
       32
       +
                   })

     

       33
       33
       +
                   .context("checking invalidity")?

     

       34
       34
       +
                   {

     

       35
       35
       +
                       // println!("{} is invalid", n);

     

       36
       36
       +
                       sum += n

     

       37
       37
       +
                   } else {

     

       38
       38
       +
                       // println!("{} is valid", n);

     

       39
       39
       +
                   }

     

       40
       40
       +
               }

     

       41
       41
       +
               Ok(sum)

     

       42
       42
       +
           }

     

       43
       43
       +
       }

     

       44
       44
       +
       

     

       45
       45
       +
       fn parse(input: &str) -> anyhow::Result<Vec<Range>> {

     

       46
       46
       +
           let input = input.trim();

     

       47
       47
       +
           let mut ranges = Vec::new();

     

       48
       48
       +
           input

     

       49
       49
       +
               .split(',')

     

       50
       50
       +
               .try_for_each(|raw_range| -> anyhow::Result<()> {

     

       51
       51
       +
                   let split_raw = raw_range.split('-').collect::<Vec<&str>>();

     

       52
       52
       +
                   let first = split_raw

     

       53
       53
       +
                       .get(0)

     

       54
       54
       +
                       .context("getting first")?

     

       55
       55
       +
                       .parse::<u128>()

     

       56
       56
       +
                       .context("parsing first")?;

     

       57
       57
       +
                   let second = split_raw

     

       58
       58
       +
                       .get(1)

     

       59
       59
       +
                       .context("getting second")?

     

       60
       60
       +
                       .parse::<u128>()

     

       61
       61
       +
                       .context("parsing second")?;

     

       62
       62
       +
                   ranges.push(Range(first, second));

     

       63
       63
       +
                   Ok(())

     

       64
       64
       +
               })

     

       65
       65
       +
               .context("running loop")?;

     

       66
       66
       +
           Ok(ranges)

     

       67
       67
       +
       }

     

       68
       68
       +
       

     

       69
       69
       +
       fn is_invalid_pt_2(num: u128) -> anyhow::Result<bool> {

     

       70
       70
       +
           let as_string = num.to_string();

     

       71
       71
       +
           let length = as_string.len();

     

       72
       72
       +
       

     

       73
       73
       +
           for i in 1..=length / 2 {

     

       74
       74
       +
               if length % i != 0 {

     

       75
       75
       +
                   continue;

     

       76
       76
       +
               }

     

       77
       77
       +
       

     

       78
       78
       +
               let pattern = &as_string[0..i];

     

       79
       79
       +
               let repetitions = length / i;

     

       80
       80
       +
       

     

       81
       81
       +
               if pattern.repeat(repetitions) == as_string {

     

       82
       82
       +
                   return Ok(true);

     

       83
       83
       +
               }

     

       84
       84
       +
           }

     

       85
       85
       +
       

     

       86
       86
       +
           Ok(false)

     

       87
       87
       +
       }

     

       88
       88
       +
       

     

       89
       89
       +
       fn is_invalid(num: u128) -> anyhow::Result<bool> {

     

       90
       90
       +
           let as_string = num.to_string();

     

       91
       91
       +
           let middle = as_string.len() / 2;

     

       92
       92
       +
       

     

       93
       93
       +
           let split = as_string.split_at(middle);

     

       94
       94
       +
       

     

       95
       95
       +
           let (left, right) = (split.0.to_string(), split.1.to_string());

     

       96
       96
       +
       

     

       97
       97
       +
           Ok(left == right)

     

       98
       98
       +
       }

src/input/2/actual.txt

···

       1
       1
       +
       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

···

       1
       1
       +
       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

···

       1
       1
        
       use anyhow::Context;

     

       2
       2
        
       

     

       3
       3
        
       mod day1;

     

       4
       4
       +
       mod day2;

     

       4
       5
        
       

     

       5
       6
        
       fn main() -> anyhow::Result<()> {

     

       6
       7
        
           println!("day 1...");

     

       7
       8
        
           day1::main().context("running day 1")?;

     

       9
       9
       +
       

     

       10
       10
       +
           println!("day 2...");

     

       11
       11
       +
           day2::main().context("running day2")?;

     

       8
       12
        
       

     

       9
       13
        
           Ok(())

     

       10
       14
        
       }