結果

問題 No.626 Randomized 01 Knapsack
ユーザー koba-e964koba-e964
提出日時 2021-09-28 18:38:39
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 4 ms / 2,000 ms
コード長 2,867 bytes
コンパイル時間 12,716 ms
コンパイル使用メモリ 387,560 KB
実行使用メモリ 6,948 KB
最終ジャッジ日時 2024-07-08 02:10:43
合計ジャッジ時間 14,288 ms
ジャッジサーバーID
(参考情報)
judge5 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 25
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#[allow(unused_imports)]
use std::cmp::*;
// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
($($r:tt)*) => {
let stdin = std::io::stdin();
let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
let mut next = move || -> String{
bytes.by_ref().map(|r|r.unwrap() as char)
.skip_while(|c|c.is_whitespace())
.take_while(|c|!c.is_whitespace())
.collect()
};
input_inner!{next, $($r)*}
};
}
macro_rules! input_inner {
($next:expr) => {};
($next:expr,) => {};
($next:expr, $var:ident : $t:tt $($r:tt)*) => {
let $var = read_value!($next, $t);
input_inner!{$next $($r)*}
};
}
macro_rules! read_value {
($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) };
($next:expr, [ $t:tt ; $len:expr ]) => {
(0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
};
($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
}
trait Change { fn chmax(&mut self, x: Self); fn chmin(&mut self, x: Self); }
impl<T: PartialOrd> Change for T {
fn chmax(&mut self, x: T) { if *self < x { *self = x; } }
fn chmin(&mut self, x: T) { if *self > x { *self = x; } }
}
fn main() {
// In order to avoid potential stack overflow, spawn a new thread.
let stack_size = 104_857_600; // 100 MB
let thd = std::thread::Builder::new().stack_size(stack_size);
thd.spawn(|| solve()).unwrap().join().unwrap();
}
fn dfs(vw: &[(i64, i64)], pos: usize, mut vsum: i64, mut wsum: i64, lim: i64, acc: i64, ma: &mut i64) {
if *ma >= acc + vsum {
return;
}
if lim >= wsum {
ma.chmax(acc + vsum);
return;
}
ma.chmax(acc);
if pos >= vw.len() {
return;
}
let mut rel = acc;
let mut rem = lim;
for i in pos..vw.len() {
let (v, w) = vw[i];
if rem >= w {
rel += v;
rem -= w;
} else {
rel += ((v as i128 * rem as i128) / w as i128) as i64;
break;
}
}
if rel <= *ma {
return;
}
let to = min(vw.len(), pos + 10);
for i in pos..to {
let (v, w) = vw[i];
vsum -= v;
wsum -= w;
if lim >= w {
dfs(vw, i + 1, vsum, wsum, lim - w, acc + v, ma);
}
}
dfs(vw, to, vsum, wsum, lim, acc, ma);
}
// The author read the editorial before implementing this.
fn solve() {
input! {
n: usize, lim: i64,
vw: [(i64, i64); n],
}
let mut vw = vw;
vw.sort_by_key(|&(v, w)| -v * 1_000_000 / w);
let mut ma = 0;
let mut vsum = 0;
let mut wsum = 0;
for i in 0..n {
vsum += vw[i].0;
wsum += vw[i].1;
}
dfs(&vw, 0, vsum, wsum, lim, 0, &mut ma);
println!("{}", ma);
}
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