make it a bitmask
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22cf7c40b1
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8e36759477
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@ -3,13 +3,16 @@ extern crate test;
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use aoc2023::{boilerplate, common::*};
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const DAY: usize = 13;
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type Parsed = Vec<Vec<Vec<bool>>>;
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type Parsed = Vec<Vec<I>>;
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type I = u32;
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fn parse_input(raw: &str) -> Parsed {
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raw.split("\n\n").map(|block| block.lines().map(|l| l.bytes().map(|b| b == b'#').collect()).collect()).collect()
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raw.split("\n\n")
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.map(|block| block.lines().map(|l| l.bytes().map(|b| b == b'#').fold(0, |acc, n| (acc << 1) | n as I)).collect())
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.collect()
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}
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fn find_reflection(block: &[Vec<bool>], blacklist: Option<usize>) -> Option<usize> {
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fn find_reflection(block: &[I], blacklist: Option<usize>) -> Option<usize> {
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'outer: for i in 0..block.len() - 1 {
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let mut offset = 0;
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loop {
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@ -30,12 +33,15 @@ fn part1(blocks: &Parsed) -> usize {
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.sum()
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}
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fn transpose(orig: &[Vec<bool>]) -> Vec<Vec<bool>> {
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let mut out = vec![vec![false; orig.len()]; orig[0].len()];
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for i in 0..orig.len() {
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#[allow(clippy::needless_range_loop)]
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for j in 0..orig[0].len() {
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out[j][i] = orig[i][j];
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fn transpose(orig: &[I]) -> Vec<I> {
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let max = orig.iter().max().unwrap();
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let len = (I::BITS - max.leading_zeros()) as usize;
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let mut out = vec![0; len];
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for j in 0..len {
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for (i, &value) in orig.iter().enumerate() {
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if (value & (1 << j)) != 0 {
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out[len - 1 - j] |= 1 << (orig.len() - 1) >> i;
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}
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}
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}
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out
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@ -49,17 +55,19 @@ fn part2(blocks: &Parsed) -> usize {
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let mut transposed = transpose(&block);
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let p1 = find_reflection(&block, None).map(|n| n - 1);
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let p1_transposed = find_reflection(&transposed, None).map(|n| n - 1);
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let max = block.iter().max().unwrap();
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let len = (I::BITS - max.leading_zeros()) as usize;
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for i in 0..block.len() {
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for j in 0..block[0].len() {
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block[i][j] ^= true;
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transposed[j][i] ^= true;
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for j in 0..len {
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block[i] ^= 1 << j;
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transposed[j] ^= 1 << i;
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if let Some(reflection) =
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find_reflection(&block, p1).map(|n| n * 100).or_else(|| find_reflection(&transposed, p1_transposed))
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{
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return reflection;
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}
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block[i][j] ^= true;
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transposed[j][i] ^= true;
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block[i] ^= 1 << j;
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transposed[j] ^= 1 << i;
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}
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}
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unreachable!()
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@ -94,7 +102,24 @@ boilerplate! {
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TEST_INPUT_VERTICAL => 300,
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},
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},
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unittests: {
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transpose: {
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&[
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0b100,
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0b010,
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] => TRANSPOSE_42,
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&[
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0b101,
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0b010,
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] => TRANSPOSE_52,
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},
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},
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bench1 == 37561,
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bench2 == 31108,
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bench_parse: Vec::len => 100,
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}
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#[cfg(test)]
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const TRANSPOSE_52: &[I] = &[0b10, 0b01, 0b10];
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#[cfg(test)]
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const TRANSPOSE_42: &[I] = &[0b10, 0b01, 0b00];
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