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Deduplicate day 12.

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Bert Peters
2018-12-13 14:47:00 +01:00
parent 91f0ec55f1
commit 0de6e22a00
1 changed files with 14 additions and 20 deletions
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34
2018/src/day12.rs
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@@ -77,29 +77,12 @@ impl Day12 {
fn simulate(&self, state: &State) -> State { fn simulate(&self, state: &State) -> State {
let mut new_state = Vec::with_capacity(state.len() + 8); let mut new_state = Vec::with_capacity(state.len() + 8);
let mut index = 0; let mut index = 0;
let mut last_idx = None;
for &(idx, b) in state { for &(idx, b) in state {
index = (index << 1) & 0x1f; index = self.advance_state(&mut new_state, index, idx, b)
if b {
index |= 1;
}
if self.productions[index] {
new_state.push((idx - 2, true));
} else if !new_state.is_empty() {
new_state.push((idx - 2, false));
}
last_idx = Some(idx);
} }
if let Some(idx) = last_idx { if let Some((idx, _)) = state.last() {
for i in 1..=4 { for i in 1..=4 {
index = (index << 1) & 0x1f; index = self.advance_state(&mut new_state, index, idx + i, false);
if self.productions[index] {
new_state.push((idx + i - 2, true));
} else if !new_state.is_empty() {
new_state.push((idx + i - 2, false));
}
} }
} }
@@ -110,6 +93,17 @@ impl Day12 {
new_state new_state
} }
fn advance_state(&self, new_state: &mut State, mut index: usize, idx: i64, b: bool) -> usize {
index = (index << 1) & 0x1f | b as usize;
if self.productions[index] {
new_state.push((idx - 2, true));
} else if !new_state.is_empty() {
new_state.push((idx - 2, false));
}
index
}
fn simulate_n(&self, mut state: State, n: usize) -> State { fn simulate_n(&self, mut state: State, n: usize) -> State {
for _ in 0..n { for _ in 0..n {
state = self.simulate(&state); state = self.simulate(&state);