64 lines
1.6 KiB
Rust
64 lines
1.6 KiB
Rust
#![feature(test)]
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extern crate test;
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const INPUTS: [&[u8]; 2] = [
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include_bytes!("./sample.txt"),
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include_bytes!("./input.txt"),
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];
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fn parse(input: &[u8]) -> Vec<i32> {
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input
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.split(|&b| b == b'\n')
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.filter(|c| !c.is_empty())
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.map(|line| {
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let isneg = line.starts_with(&[b'-']);
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let num = line
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.iter()
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.filter(|c| (b'0'..=b'9').contains(c))
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.fold(0, |a, x| (a * 10) + (x - b'0') as i32);
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if isneg {
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-num
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} else {
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num
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}
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})
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.collect()
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}
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fn solution(input: Vec<i32>) -> i32 {
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let l = input.len() as i32;
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let mut idxes = (0..l as usize).collect::<Vec<usize>>();
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for (i, num) in input.iter().enumerate() {
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let pos = idxes.iter().position(|&c| c == i).unwrap();
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idxes.remove(pos);
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let new_idx = (pos as i32 + num).rem_euclid(idxes.len() as i32) as usize;
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idxes.insert(new_idx, i);
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}
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let orig_zero_i = input.iter().position(|&i| i == 0).unwrap();
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let zero_i = idxes.iter().position(|&i| i == orig_zero_i).unwrap();
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[1000, 2000, 3000]
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.iter()
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.map(|i| input[idxes[(zero_i + i) % idxes.len()]])
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.sum()
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}
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fn main() {
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for input in INPUTS.iter() {
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let output = parse(input);
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let score = solution(output);
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println!("{}", score);
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}
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}
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#[bench]
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fn solution_bench(b: &mut test::Bencher) {
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b.iter(|| {
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let input = parse(INPUTS[1]);
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let result = solution(input);
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test::black_box(result);
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})
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}
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