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40 lines
928 B
40 lines
928 B
use std::collections::HashSet;
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use std::error;
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use std::fs::File;
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use std::io::prelude::*;
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const N_CHARS: usize = 14;
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fn main() -> Result<(), Box<dyn error::Error>> {
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let mut f = File::open("input.txt")?;
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let mut buf = [0; 32];
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let mut pos = 0;
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let mut found = false;
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let mut n = f.read(&mut buf[(N_CHARS - 1)..])?;
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while n > 0 {
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for i in N_CHARS..(N_CHARS + n) {
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pos += 1;
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// println!("{}", std::str::from_utf8(&buf[(i - N_CHARS)..i]).unwrap());
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// skip if we read uninitialized data from first run
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if buf[i - N_CHARS] == 0 {
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continue;
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}
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let set: HashSet<&u8> = HashSet::from_iter(&buf[(i - N_CHARS)..i]);
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if set.len() == N_CHARS {
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found = true;
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break;
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}
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}
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if found {
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break;
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}
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for i in 0..(N_CHARS - 1) {
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buf[i] = buf[(32 - N_CHARS + 1) + i];
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}
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n = f.read(&mut buf[(N_CHARS - 1)..])?;
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}
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println!("Found 4 different chars at position {}", pos);
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Ok(())
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}
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