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38 lines
812 B
38 lines
812 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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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[3..])?;
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while n > 0 {
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for i in 4..(4 + n) {
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pos += 1;
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// println!("{}", std::str::from_utf8(&buf[(i - 4)..i]).unwrap());
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// skip if we read uninitialized data from first run
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if buf[i - 4] == 0 {
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continue;
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}
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let set: HashSet<&u8> = HashSet::from_iter(&buf[(i - 4)..i]);
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if set.len() == 4 {
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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..3 {
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buf[i] = buf[29 + i];
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}
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n = f.read(&mut buf[3..])?;
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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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