43 lines
1.1 KiB
Rust
43 lines
1.1 KiB
Rust
#[cfg(debug_assertions)]
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const LENGTH: usize = 5;
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#[cfg(not(debug_assertions))]
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const LENGTH: usize = 3_017_957;
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fn main() {
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let mut pointer = 0;
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let mut has_presents = [true; LENGTH];
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let mut next_elf = [0; LENGTH];
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for (idx, val) in next_elf.iter_mut().enumerate() {
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*val = (idx + 1) % LENGTH;
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}
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'outer: loop {
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let mut offset = 1;
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loop {
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let idx = (pointer + offset) % LENGTH;
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if has_presents[idx] {
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has_presents[idx] = false;
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pointer = idx;
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break;
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} else {
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offset += 1;
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}
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}
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let count = has_presents.iter().filter(|b| **b).count();
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println!("{count}");
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if count == 1 {
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let correct_idx = has_presents
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.iter()
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.enumerate()
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.filter(|(_, b)| **b)
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.map(|(i, _)| i)
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.next()
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.unwrap()
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+ 1;
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println!("{correct_idx}");
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break 'outer;
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}
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}
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}
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