#906809 (Rust) No.2438 Double Least Square

• 問題: No.2438 Double Least Square
• ユーザー: koba-e964
• 提出日時: 2023-08-22 10:02:48
• 言語: Rust (1.83.0 + proconio)
• 結果: WA
• 実行時間: -
• コード長: 2,951 bytes
• コンパイル時間: 15,378 ms
• コンパイル使用メモリ: 376,716 KB
• 実行使用メモリ: 6,824 KB
• 最終ジャッジ日時: 2024-12-16 05:56:47
• 合計ジャッジ時間: 16,987 ms
• ジャッジサーバーID （参考情報）: judge4 / judge3

ファイルパターン	結果
sample	AC * 3
other	AC * 19 WA * 11

コンパイルメッセージ

warning: variable `hsum` is assigned to, but never used
  --> src/main.rs:65:13
   |
65 |     let mut hsum = 0.0;
   |             ^^^^
   |
   = note: consider using `_hsum` instead
   = note: `#[warn(unused_variables)]` on by default

ソースコード

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#[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, 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);
        read_value!($next, [$t; len])
    }};
    ($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 solve() {
    input! {
        n: usize,
        h: f64,
        xy: [(f64, f64); n],
    }
    let mut a1 = 0.0;
    let mut a2 = 0.0;
    // adagrad
    let mut hsum = 0.0;
    for _ in 0..4000 {
        let mut g1 = 0.0;
        let mut g2 = 0.0;
        let mut gg1 = 0.0;
        let mut gg2 = 0.0;
        for &(x, y) in &xy {
            if (x * a2 - y).abs() < (x * a1 + h - y).abs() {
                g2 += x * (x * a2 - y);
                gg2 += x * x;
            } else {
                g1 += x * (x * a1 + h - y);
                gg1 += x * x;
            }
        }
        if g1 == 0.0 && g2 == 0.0 {
            break;
        }
        eprintln!("g = {} {}", g1, g2);
        let g = g1 * g1 + g2 * g2;
        hsum += g;
        if gg1 > 0.0 {
            a1 -= g1 / gg1;
        }
        if gg2 > 0.0 {
            a2 -= g2 / gg2;
        }
        eprintln!("new a = {} {}", a1, a2);
    }
    eprintln!("{} {}", a1, a2);
    let mut ans = 0.0;
    for &(x, y) in &xy {
        let tmp = (x * a2 - y).abs().min((x * a1 + h - y).abs());
        ans += tmp * tmp;
    }
    println!("{}", ans);
}
 
 
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