bwc9876.dev
Advent of Code solutions
Day 3
+67
-6
+59
-6
years/2025/src/day_3.rs
+59
-6
years/2025/src/day_3.rs
···
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use advent_core::{Day, day_stuff, ex_for_day};
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pub struct Day3;
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impl Day for Day3 {
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day_stuff!(3, "357", "3121910778619", Vec<Vec<usize>>);
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day_stuff!(3, "", "");
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fn part_1(input: Self::Input) -> Option<String> {
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let ans = input
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.into_iter()
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.map(|bank| {
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let (largest_idx, largest) = bank
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.iter()
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.enumerate()
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.take(bank.len() - 1)
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.rev()
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.max_by(|(_, x), (_, y)| (**x).cmp(*y))
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.map(|(i, x)| (i, *x))
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.unwrap();
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let rest = bank.into_iter().skip(largest_idx + 1);
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let next_largest = rest.max().unwrap();
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largest * 10 + next_largest
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})
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.sum::<usize>();
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Some(ans.to_string())
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}
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fn part_2(input: Self::Input) -> Option<String> {
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let ans = input
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.into_iter()
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.map(|bank| {
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let mut num = 0;
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let mut start = 0;
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for i in 0..12 {
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let (idx, largest) = bank
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.iter()
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.enumerate()
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.filter(|(idx, _)| {
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(i == 0 || *idx > start) && *idx + (11 - i) <= (bank.len() - 1)
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})
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.rev()
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.max_by(|(_, x), (_, y)| (**x).cmp(*y))
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.map(|(idx, x)| (idx, *x))
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.unwrap();
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fn part_1(_input: Self::Input) -> Option<String> {
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None
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num += largest * 10_usize.pow((11 - i) as u32);
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start = idx;
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}
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num
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})
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.sum::<usize>();
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Some(ans.to_string())
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}
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fn part_2(_input: Self::Input) -> Option<String> {
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None
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fn parse_input(input: &str) -> Self::Input {
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input
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.lines()
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.map(|l| {
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l.trim()
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.chars()
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.map(|c| c.to_digit(10).unwrap() as usize)
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.collect()
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})
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.collect()
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}
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}
+4
years/2025/src/examples/day_3/1.txt
+4
years/2025/src/examples/day_3/1.txt