結果

問題 No.2058 Binary String
ユーザー 12345
提出日時 2022-08-26 22:37:13
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 310 ms / 2,000 ms
コード長 2,854 bytes
コンパイル時間 11,593 ms
コンパイル使用メモリ 387,688 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-10-13 23:15:37
合計ジャッジ時間 16,115 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
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ファイルパターン 結果
sample AC * 3
other AC * 23
権限があれば一括ダウンロードができます
コンパイルメッセージ
warning: variable does not need to be mutable
  --> src/main.rs:7:13
   |
7  |           let mut s = {
   |               ----^
   |               |
   |               help: remove this `mut`
...
84 | /     input! {
85 | |         n: i64,
86 | |         k: i64,
87 | |     };
   | |_____- in this macro invocation
   |
   = note: `#[warn(unused_mut)]` on by default
   = note: this warning originates in the macro `input` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: variable does not need to be mutable
   --> src/main.rs:106:9
    |
106 |     let mut finv: Vec<_> = fact.iter().map(|x| modinv(*x, m)).collect();
    |         ----^^^^
    |         |
    |         help: remove this `mut`

ソースコード

diff #
プレゼンテーションモードにする

macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let mut s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
fn search(x: i64) -> i64 {
    if x == 0 {
        return 0;
    }
    for i in 0..100 {
        if (x & (1 << i)) != 0 {
            return 1+  search(x ^ (1 << i) ^ (1 << (i + 1)));
        }
    }
    panic!();
}
fn modpow(x: i64, p: i64, m: i64) -> i64 {
    if p == 0 {
        1
    } else if p == 1 {
        x
    } else if p % 2 == 1 {
        x * modpow(x, p - 1, m) % m
    } else {
        let t = modpow(x, p / 2, m);
        t * t % m
    }
}
fn modinv(x: i64, m: i64) -> i64{
    modpow(x, m - 2, m)
}
fn main() {
    let m = 998244353;
    input! {
        n: i64,
        k: i64,
    };
    if false {
        let mut cnt = vec![0; 10];
        for b in 0..(1 << n) {
            let x: i64 = b;
            if x.count_ones() % 2 == 0 {
                let r = search(x);
                println!("{:b} {} {}", x, x.count_ones(), r);
                cnt[r as usize] += 1;
            }
        }
        //dbg!(&cnt);
    }
    let mut fact = vec![1; (n + 1) as usize];
    for i in 1.. (n + 1) {
        fact[i as usize] = fact[(i - 1) as usize] * (i as i64) % m;
    }
    let mut finv: Vec<_> = fact.iter().map(|x| modinv(*x, m)).collect();
    // dbg!(&fact);
    // dbg!(&finv);
    //
    // for i in 0 ..(n + 1) {
    //     fact[i as usize] = modpow(fact[i as usize], k, m);
    //     finv[i as usize] = modpow(finv[i as usize], k, m);
    //     dbg!(&fact[i as usize] * finv[i as usize] % m);
    // }
    let mut s = 0;
    for i in 0..n {
        let t = fact[(n - 1) as usize] % m * finv[i as usize] % m * finv[(n - i - 1) as usize] % m;
        //dbg!(&t);
        s += modpow(i, k, m) * t;
        s %= m;
    }
    println!("{}", s);
}
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