結果

問題 No.811 約数の個数の最大化
ユーザー koba-e964koba-e964
提出日時 2019-06-26 02:12:16
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 22 ms / 2,000 ms
コード長 2,991 bytes
コンパイル時間 17,637 ms
コンパイル使用メモリ 398,268 KB
実行使用メモリ 6,944 KB
最終ジャッジ日時 2024-06-23 16:06:37
合計ジャッジ時間 15,291 ms
ジャッジサーバーID
(参考情報)
judge4 / judge1
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 12
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::*;
#[allow(unused_imports)]
use std::collections::*;
use std::io::{Write, BufWriter};
// 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, chars) => {
read_value!($next, String).chars().collect::<Vec<char>>()
};
($next:expr, usize1) => {
read_value!($next, usize) - 1
};
($next:expr, [ $t:tt ]) => {{
let len = read_value!($next, usize);
(0..len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
}};
($next:expr, $t:ty) => {
$next().parse::<$t>().expect("Parse error")
};
}
fn gcd(mut x: i64, mut y: i64) -> i64 {
while y != 0 {
let r = x % y;
x = y; y = r;
}
x
}
fn solve() {
let out = std::io::stdout();
let mut out = BufWriter::new(out.lock());
macro_rules! puts {
($($format:tt)*) => (write!(out,$($format)*).unwrap());
}
input! {
n: usize, k: usize,
}
const W: usize = 100_001;
let mut fac = vec![0; W];
for i in 2..W {
if fac[i] != 0 {
continue;
}
fac[i] = i;
let mut j = 2 * i;
while j < W {
fac[j] = i;
j += i;
}
}
let mut faccnt = vec![0; W];
let mut divcnt = vec![1; W];
for i in 2..W {
let mut v = i;
while v > 1 {
let p = fac[v];
let mut e = 0;
while v % p == 0 {
v /= p;
e += 1;
faccnt[i] += 1;
}
divcnt[i] *= e + 1;
}
}
let mut ma = (0, Reverse(0));
for i in 1..n {
let g = gcd(i as i64, n as i64) as usize;
if faccnt[g] < k { continue; }
ma = max(ma, (divcnt[i], Reverse(i)));
}
puts!("{}\n", (ma.1).0);
}
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();
}
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