bwc9876.dev
Advent of Code solutions
Day 6
+106
-6
+98
-6
years/2025/src/day_6.rs
+98
-6
years/2025/src/day_6.rs
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use advent_core::{Day, day_stuff, ex_for_day};
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pub struct Day6;
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#[derive(Debug, Clone)]
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pub enum Prob {
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Add(Vec<usize>),
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Mul(Vec<usize>),
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}
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impl Day for Day6 {
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day_stuff!(6, "4277556", "3263827");
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day_stuff!(6, "", "");
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fn part_1(input: Self::Input) -> Option<String> {
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let uno = input.lines().collect::<Vec<_>>();
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let dos = uno
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.iter()
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.take(uno.len() - 1)
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.map(|l| {
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l.split_whitespace()
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.map(|p| p.parse::<usize>().unwrap())
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.collect::<Vec<_>>()
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})
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.collect::<Vec<_>>();
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let ops = uno
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.iter()
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.skip(uno.len() - 1)
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.next()
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.unwrap()
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.split_whitespace()
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.collect::<Vec<_>>();
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let mut problems = Vec::with_capacity(uno.len());
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fn part_1(_input: Self::Input) -> Option<String> {
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None
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for i in 0..dos[0].len() {
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let all_operands = dos.iter().map(|d| d[i]).collect::<Vec<_>>();
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let operator = ops[i];
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let prob = if operator == "*" {
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Prob::Mul(all_operands)
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} else {
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Prob::Add(all_operands)
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};
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problems.push(prob);
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}
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let ans = problems
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.into_iter()
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.map(|p| match p {
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Prob::Add(l) => l.iter().sum::<usize>(),
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Prob::Mul(l) => l.iter().copied().reduce(|a, b| a * b).unwrap(),
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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 part_2(input: Self::Input) -> Option<String> {
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let mut cols: Vec<Vec<_>> = vec![];
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for (_, row) in input.lines().enumerate() {
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for (j, c) in row.chars().enumerate() {
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if let Some(r) = cols.get_mut(j) {
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r.push(c);
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} else {
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cols.push(vec![c]);
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}
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}
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}
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let mut curr_val = 0;
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let mut curr_op: Option<char> = None;
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let mut tot = 0;
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for col in cols {
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if let Some(op) = curr_op {
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if col.iter().all(|c| *c == ' ') {
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tot += curr_val;
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curr_val = 0_usize;
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curr_op = None;
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} else {
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let num = col
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.iter()
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.collect::<String>()
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.trim()
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.parse::<usize>()
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.unwrap();
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if op == '+' {
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curr_val += num;
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} else {
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curr_val *= num;
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}
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}
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} else {
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curr_op = Some(col.last().copied().unwrap());
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curr_val = col
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.iter()
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.take(col.len() - 1)
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.collect::<String>()
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.trim()
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.parse::<usize>()
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.unwrap();
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}
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}
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tot += curr_val;
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Some(tot.to_string())
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}
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}
+4
years/2025/src/examples/day_6/1.txt
+4
years/2025/src/examples/day_6/1.txt