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use std::io;
use std::io::BufRead;
use std::fmt;
struct Chain<T: Copy> {
left: Vec<T>,
right: Vec<T>,
}
impl<T: Copy> Chain<T> {
fn new() -> Self {
Chain { left: Vec::new(), right: Vec::new() }
}
fn redistribute(&mut self) {
// println!("redistribute: left {}, right {}", self.left.len(), self.right.len());
let large;
let small;
if self.left.len() > self.right.len() {
large = &mut self.left;
small = &mut self.right;
} else {
large = &mut self.right;
small = &mut self.left;
}
if large.len() == 0 {
return;
}
let mut temp = Vec::new();
temp.append(small);
// This seems fast in my tests, for some reason
let denominator = 10;
let nmoved = (large.len() * (denominator - 1) + denominator - 1) / denominator;
for i in 0..nmoved {
small.push(large[nmoved - 1 - i]);
}
large.splice(..nmoved, std::iter::empty());
small.append(&mut temp);
// println!(" left {}, right {}", self.left.len(), self.right.len());
}
fn rot_left(&mut self) {
if self.left.len() + self.right.len() == 0 {
return;
}
if self.left.len() == 0 {
self.redistribute();
}
self.right.push(*self.left.last().unwrap());
self.left.pop();
}
fn rot_right(&mut self) {
if self.left.len() + self.right.len() == 0 {
return;
}
if self.right.len() == 0 {
self.redistribute();
}
self.left.push(*self.right.last().unwrap());
self.right.pop();
}
fn current(&self) -> T {
if self.left.len() == 0 {
*self.right.first().unwrap()
} else {
*self.left.last().unwrap()
}
}
fn rotate(&mut self, amt: i32) {
if amt < 0 {
for _ in 0..-amt { self.rot_left(); }
} else {
for _ in 0..amt { self.rot_right(); }
}
}
fn insert_after(&mut self, val: T) {
self.left.push(val);
}
#[used]
fn insert_before(&mut self, val: T) {
if self.left.len() == 0 {
if self.right.len() == 0 {
self.left.push(val);
return;
}
self.redistribute();
}
self.left.insert(self.left.len() - 1, val);
}
fn remove_current(&mut self) {
if self.left.len() == 0 {
self.right.remove(0);
} else {
self.left.pop();
}
}
}
impl<T: Copy + fmt::Display> fmt::Display for Chain<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if self.left.len() == 0 {
if self.right.len() == 0 { return Ok(()); }
write!(f, "({})", self.right[0])?;
for i in 0..self.right.len()-1 {
write!(f, " {}", self.right[self.right.len() - 1 - i])?;
}
} else {
for val in self.left.iter().take(self.left.len() - 1) {
write!(f, "{} ", val)?;
}
write!(f, "({})", self.left.last().unwrap())?;
for i in 0..self.right.len() {
write!(f, " {}", self.right[self.right.len() - 1 - i])?;
}
}
Ok(())
}
}
fn simulate(nplayers: i64, lastmarble: i64) -> i64 {
let mut scores = vec![0; nplayers as usize];
let mut chain: Chain<i64> = Chain::new();
chain.insert_after(0);
// println!("{}", chain);
for marble in 1..lastmarble+1 {
if marble % 23 != 0 {
chain.rotate(1);
chain.insert_after(marble);
} else {
scores[(marble % nplayers) as usize] += marble;
chain.rotate(-7);
scores[(marble % nplayers) as usize] += chain.current();
chain.remove_current();
chain.rotate(1);
}
// println!("{}", chain);
}
*scores.iter().max().unwrap()
}
pub fn main<T: BufRead>(reader: T) -> io::Result<(String, String)> {
let input = reader.lines().next().unwrap().unwrap();
let input_split: Vec<&str> = input.split(' ').collect();
let nplayers: i64 = input_split[0].parse().unwrap();
let lastmarble: i64 = input_split[6].parse().unwrap();
let part1 = simulate(nplayers, lastmarble).to_string();
let part2 = simulate(nplayers, lastmarble * 100).to_string();
Ok((part1, part2))
}
|
