day 2b solved!

This commit is contained in:
Tabby 2025-12-02 12:12:34 +00:00
parent b9dc620b95
commit 8e0b080f3b
6 changed files with 213 additions and 2 deletions

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aoc-2b/src/example.txt Normal file
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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

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aoc-2b/src/input.txt Normal file
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5959566378-5959623425,946263-1041590,7777713106-7777870316,35289387-35394603,400-605,9398763-9592164,74280544-74442206,85684682-85865536,90493-179243,202820-342465,872920-935940,76905692-76973065,822774704-822842541,642605-677786,3759067960-3759239836,1284-3164,755464-833196,52-128,3-14,30481-55388,844722790-844967944,83826709-83860070,9595933151-9595993435,4216-9667,529939-579900,1077949-1151438,394508-486310,794-1154,10159-17642,5471119-5683923,16-36,17797-29079,187-382

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aoc-2b/src/main.rs Normal file
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// within certain rnages, find numbers with a pattern repeated exactly twice
// eg "55" ("5" twice), "6464" ("64" twice), "123123"
// cannot be matches on numebrs with an odd number of digits
// compare the first half of the didgits to the second half
// save all the matches (invalid id's) to a list and add them up to produce the solution
// each rnage can have 0 or more invalid id's
// need to parse each range (probably regex), get start and end value for each
use std::fs;
use regex::Regex;
fn main() {
println!("Lets begin, day 2, part 1");
let file_path = "src/input.txt";
// let file_path = "src/example.txt";
// split up input by "," and "-"
// (?<start_range>\d*)-(?<end_range>\d*)
let re = Regex::new(r"(?<start_range>\d*)-(?<end_range>\d*)").unwrap();
let line = fs::read_to_string(file_path).unwrap();
println!("{line}");
let mut invalids: Vec<i64> = Vec::new();
// parse the provided ranges into paits
let ranges: Vec<(&str, &str)> = re.captures_iter(&line).map(|caps| {
let start = caps.name("start_range").unwrap().as_str();
let end = caps.name("end_range").unwrap().as_str();
(start, end)
}).collect();
println!("{ranges:?}");
for range in ranges{
println!("working on: {range:?}");
let start = range.0.parse::<i64>().unwrap();
let end = range.1.parse::<i64>().unwrap();
// println!("{range.0:?} --> {end}");
let mut count :i64 = start;
while count <= end{
// if odd number of didgits, then no match, skip to next loop
// if even number, then compare the first and second half
let current = count.to_string();
if find_invalid(current){
invalids.push(count);
}
// if current.len() % 2 != 1{
// let half_len = current.len()/2;
// let half_a = &current[..half_len];
// let half_b = &current[half_len..];
// let current_str = current.to_string();
// println!("{current_str} = {half_a} + {half_b}");
// if half_a == half_b{
// invalids.push(count);
// }
// }
count += 1;
}
}
println!("{invalids:?}");
let mut solution: i64 = 0;
for result in invalids{
solution += result;
}
println!("Puzzle Solution: {solution}")
// Correct :3
}
fn find_invalid(text : String) -> bool{
// let mut invalid = false;
// 1x matches
if text.len() > 1{
let one = text.chars().nth(0).unwrap();
let mut ones_match = true;
for char in text.chars(){
if char == one{
// good
}
else{
ones_match = false;
}
}
if ones_match{
return true;
}
}
// 2x matches
if text.len() == 4{
if &text[0..2] == &text[2..4]{
return true;
}
}
else if text.len() == 6{
if &text[0..2] == &text[2..4] && &text[0..2] == &text[4..6]{
return true;
}
}
else if text.len() == 8{
if &text[0..2] == &text[2..4] && &text[0..2] == &text[4..6] && &text[0..2] == &text[6..8]{
return true;
}
}
else if text.len() == 10{
if &text[0..2] == &text[2..4] && &text[0..2] == &text[4..6] && &text[0..2] == &text[6..8] && &text[0..2] == &text[8..10]{
return true;
}
}
// 3x matches
if text.len() == 6 {
if &text[0..3] == &text[3..6]{
return true;
}
}
if text.len() == 9 {
if &text[0..3] == &text[3..6] && &text[0..3] == &text[6..9]{
return true;
}
}
// 4x matches
if text.len() == 8 {
if &text[0..4] == &text[4..8]{
return true;
}
}
// 5x matches
if text.len() == 10{
if &text[0..5] == &text[5..10]{
return true;
}
}
return false; // represents no match
}
// tried: 36862281460 - too high
// solved! second attempt