結果

問題 No.1879 How many matchings?
ユーザー koba-e964
提出日時 2022-03-18 22:51:29
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 1 ms / 2,000 ms
コード長 2,547 bytes
コンパイル時間 11,016 ms
コンパイル使用メモリ 394,860 KB
実行使用メモリ 6,820 KB
最終ジャッジ日時 2024-10-03 07:51:43
合計ジャッジ時間 11,761 ms
ジャッジサーバーID
(参考情報)
judge3 / judge5
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 * 15
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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::Read;
#[allow(dead_code)]
fn getline() -> String {
let mut ret = String::new();
std::io::stdin().read_line(&mut ret).ok().unwrap();
ret
}
fn get_word() -> String {
let stdin = std::io::stdin();
let mut stdin=stdin.lock();
let mut u8b: [u8; 1] = [0];
loop {
let mut buf: Vec<u8> = Vec::with_capacity(16);
loop {
let res = stdin.read(&mut u8b);
if res.unwrap_or(0) == 0 || u8b[0] <= b' ' {
break;
} else {
buf.push(u8b[0]);
}
}
if buf.len() >= 1 {
let ret = String::from_utf8(buf).unwrap();
return ret;
}
}
}
#[allow(dead_code)]
fn get<T: std::str::FromStr>() -> T { get_word().parse().ok().unwrap() }
fn squmul(a: &[Vec<i64>], b: &[Vec<i64>], mo: i64) -> Vec<Vec<i64>> {
let n = a.len();
let mut ret = vec![vec![0; n]; n];
for i in 0..n {
for j in 0..n {
for k in 0..n {
ret[i][k] += a[i][j] * b[j][k];
ret[i][k] %= mo;
}
}
}
ret
}
fn squpow(a: &[Vec<i64>], mut e: i64, mo: i64) -> Vec<Vec<i64>> {
let n = a.len();
let mut sum = vec![vec![0; n]; n];
for i in 0..n { sum[i][i] = 1; }
let mut cur = a.to_vec();
while e > 0 {
if e % 2 == 1 {
sum = squmul(&sum, &cur, mo);
}
cur = squmul(&cur, &cur, mo);
e /= 2;
}
sum
}
fn solve() {
let n: i64 = get();
const MOD: i64 = 1_000_000_007;
let mut mat;
if n % 2 == 0 {
mat = vec![vec![0; 4]; 4];
for i in 0..2 {
mat[i][2 * i + 1] += 1;
mat[2 + i][2 * i] += 1;
}
mat[1][0] += 1;
} else {
mat = vec![vec![0; 8]; 8];
for j in 0..2 {
for i in 0..2 {
mat[4 * j + i][4 * j + 2 * i + 1] += 1;
mat[4 * j + 2 + i][4 * j + 2 * i] += 1;
}
mat[4 * j + 1][4 * j] += 1;
}
for i in 0..2 {
mat[i][4 + 2 * i] += 1;
}
}
let pw = squpow(&mat, n, MOD);
let ans = pw[0][4 * (n % 2) as usize];
println!("{}", ans);
}
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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