結果

問題 No.1178 Can you draw a Circle?
ユーザー cotton_fn_
提出日時 2020-12-08 03:37:40
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 2 ms / 2,000 ms
コード長 10,372 bytes
コンパイル時間 13,157 ms
コンパイル使用メモリ 378,104 KB
実行使用メモリ 5,376 KB
最終ジャッジ日時 2024-09-17 14:19:48
合計ジャッジ時間 14,032 ms
ジャッジサーバーID
(参考情報)
judge5 / judge4
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
sample AC * 2
other AC * 15
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, unused_macros)]
use kyoproio::*;
use std::{
collections::*,
io::{self, prelude::*},
iter,
mem::{replace, swap},
};
fn run<I: Input, O: Write>(mut kin: I, out: O) {
let mut out = KOutput::new(out);
let [a, b, c, d, e, f]: [f64; 6] = kin.input();
// ax^2 + by^2 + cx + dy + e = f
// u((x - s)^2 + (y - t)^2) = ur^2
// u(x^2 - 2sx + s^2 + y^2 - 2ty + t^2) = ur^2
// u = a = b
// s = -c / 2u
// t = -d / 2u
// u(r^2 - s^2 - t^2) = f - e
// r^2 = (f - e + (c ^ 2 + d ^ 2) / 4a) / a
assert_eq!(a, b);
let r2 = (f - e + (c * c + d * d) / (4. * a)) / a;
let r = r2.sqrt();
outln!(out, r);
}
// -----------------------------------------------------------------------------
fn main() -> io::Result<()> {
std::thread::Builder::new()
.stack_size(64 * 1024 * 1024)
.spawn(|| {
run(
KInput::new(io::stdin().lock()),
io::BufWriter::new(io::stdout().lock()),
)
})?
.join()
.unwrap();
Ok(())
}
// -----------------------------------------------------------------------------
pub mod kyoproio {
use std::{
io::prelude::*,
iter::FromIterator,
marker::PhantomData,
mem::{self, MaybeUninit},
ptr, slice, str,
};
pub trait Input {
fn bytes(&mut self) -> &[u8];
fn str(&mut self) -> &str {
str::from_utf8(self.bytes()).unwrap()
}
fn input<T: InputItem>(&mut self) -> T {
T::input(self)
}
fn iter<T: InputItem>(&mut self) -> Iter<T, Self> {
Iter(self, PhantomData)
}
fn seq<T: InputItem, B: FromIterator<T>>(&mut self, n: usize) -> B {
self.iter().take(n).collect()
}
}
pub struct KInput<R> {
src: R,
buf: Vec<u8>,
pos: usize,
len: usize,
}
impl<R: Read> KInput<R> {
pub fn new(src: R) -> Self {
Self {
src,
buf: vec![0; 1 << 16],
pos: 0,
len: 0,
}
}
fn read(&mut self) -> usize {
if self.pos > 0 {
self.buf.copy_within(self.pos..self.len, 0);
self.len -= self.pos;
self.pos = 0;
} else if self.len >= self.buf.len() {
self.buf.resize(2 * self.buf.len(), 0);
}
let read = self.src.read(&mut self.buf[self.len..]).unwrap();
self.len += read;
read
}
}
impl<R: Read> Input for KInput<R> {
fn bytes(&mut self) -> &[u8] {
loop {
while let Some(d) = self.buf[self.pos..self.len]
.iter()
.position(u8::is_ascii_whitespace)
{
let p = self.pos;
self.pos += d + 1;
if d > 0 {
return &self.buf[p..p + d];
}
}
if self.read() == 0 {
return &self.buf[mem::replace(&mut self.pos, self.len)..self.len];
}
}
}
}
pub struct Iter<'a, T, I: ?Sized>(&'a mut I, PhantomData<*const T>);
impl<'a, T: InputItem, I: Input + ?Sized> Iterator for Iter<'a, T, I> {
type Item = T;
fn next(&mut self) -> Option<T> {
Some(self.0.input())
}
fn size_hint(&self) -> (usize, Option<usize>) {
(!0, None)
}
}
pub trait InputItem: Sized {
fn input<I: Input + ?Sized>(src: &mut I) -> Self;
}
impl InputItem for Vec<u8> {
fn input<I: Input + ?Sized>(src: &mut I) -> Self {
src.bytes().to_owned()
}
}
macro_rules! from_str {
{ $($T:ty)* } => {
$(impl InputItem for $T {
fn input<I: Input + ?Sized>(src: &mut I) -> Self {
src.str().parse::<$T>().unwrap()
}
})*
}
}
from_str! { String char bool f32 f64 }
macro_rules! parse_int {
{ $($I:ty: $U:ty)* } => {
$(impl InputItem for $I {
fn input<I: Input + ?Sized>(src: &mut I) -> Self {
let f = |s: &[u8]| s.iter().fold(0, |x, b| 10 * x + (b & 0xf) as $I);
let s = src.bytes();
if let Some((&b'-', t)) = s.split_first() { -f(t) } else { f(s) }
}
}
impl InputItem for $U {
fn input<I: Input + ?Sized>(src: &mut I) -> Self {
src.bytes().iter().fold(0, |x, b| 10 * x + (b & 0xf) as $U)
}
})*
};
}
parse_int! { isize:usize i8:u8 i16:u16 i32:u32 i64:u64 i128:u128 }
macro_rules! tuple {
($H:ident $($T:ident)*) => {
impl<$H: InputItem, $($T: InputItem),*> InputItem for ($H, $($T),*) {
fn input<I: Input + ?Sized>(src: &mut I) -> Self {
($H::input(src), $($T::input(src)),*)
}
}
tuple!($($T)*);
};
() => {}
}
tuple!(A B C D E F G);
macro_rules! array {
{ $($N:literal)* } => {
$(impl<T: InputItem> InputItem for [T; $N] {
fn input<I: Input + ?Sized>(src: &mut I) -> Self {
let mut arr = MaybeUninit::uninit();
let ptr = arr.as_mut_ptr() as *mut T;
unsafe {
for i in 0..$N {
ptr.add(i).write(src.input());
}
arr.assume_init()
}
}
})*
};
}
array! { 1 2 3 4 5 6 7 8 }
pub struct KOutput<W: Write> {
dest: W,
delim: bool,
}
impl<W: Write> KOutput<W> {
pub fn new(dest: W) -> Self {
Self { dest, delim: false }
}
pub fn bytes(&mut self, s: &[u8]) {
self.dest.write_all(s).unwrap();
}
pub fn byte(&mut self, b: u8) {
self.bytes(slice::from_ref(&b));
}
pub fn output<T: OutputItem>(&mut self, x: T) {
if self.delim {
self.byte(b' ');
}
self.delim = true;
x.output(self);
}
pub fn ln(&mut self) {
self.delim = false;
self.byte(b'\n');
self.flush_debug();
}
pub fn inner(&mut self) -> &mut W {
&mut self.dest
}
pub fn seq<T: OutputItem, I: IntoIterator<Item = T>>(&mut self, iter: I) {
for x in iter.into_iter() {
self.output(x);
}
}
pub fn flush(&mut self) {
self.dest.flush().unwrap();
}
pub fn flush_debug(&mut self) {
if cfg!(debug_assertions) {
self.flush();
}
}
}
pub trait OutputItem {
fn output<W: Write>(self, dest: &mut KOutput<W>);
}
impl OutputItem for &str {
fn output<W: Write>(self, dest: &mut KOutput<W>) {
dest.bytes(self.as_bytes());
}
}
impl OutputItem for char {
fn output<W: Write>(self, dest: &mut KOutput<W>) {
self.encode_utf8(&mut [0; 4]).output(dest);
}
}
macro_rules! output_fmt {
($($T:ty)*) => {
$(impl OutputItem for $T {
fn output<W: Write>(self, dest: &mut KOutput<W>) {
write!(dest.inner(), "{}", self).unwrap();
}
})*
}
}
output_fmt!(f32 f64);
macro_rules! output_int {
($conv:ident; $U:ty; $($T:ty)*) => {
$(impl OutputItem for $T {
fn output<W: Write>(self, dest: &mut KOutput<W>) {
let mut buf = MaybeUninit::<[u8; 20]>::uninit();
unsafe {
let ptr = buf.as_mut_ptr() as *mut u8;
let ofs = $conv(self as $U, ptr, 20);
dest.bytes(slice::from_raw_parts(ptr.add(ofs), 20 - ofs));
}
}
}
impl OutputItem for &$T {
fn output<W: Write>(self, dest: &mut KOutput<W>) {
(*self).output(dest);
}
})*
};
}
output_int!(i64_to_bytes; i64; isize i8 i16 i32 i64);
output_int!(u64_to_bytes; u64; usize u8 u16 u32 u64);
static DIGITS_LUT: &[u8; 200] = b"0001020304050607080910111213141516171819\
2021222324252627282930313233343536373839\
4041424344454647484950515253545556575859\
6061626364656667686970717273747576777879\
8081828384858687888990919293949596979899";
unsafe fn i64_to_bytes(x: i64, buf: *mut u8, len: usize) -> usize {
let (neg, x) = if x < 0 { (true, -x) } else { (false, x) };
let mut i = u64_to_bytes(x as u64, buf, len);
if neg {
i -= 1;
*buf.add(i) = b'-';
}
i
}
unsafe fn u64_to_bytes(mut x: u64, buf: *mut u8, len: usize) -> usize {
let lut = DIGITS_LUT.as_ptr();
let mut i = len;
let mut two = |x| {
i -= 2;
ptr::copy_nonoverlapping(lut.add(2 * x), buf.add(i), 2);
};
while x >= 10000 {
let rem = (x % 10000) as usize;
two(rem % 100);
two(rem / 100);
x /= 10000;
}
let mut x = x as usize;
if x >= 100 {
two(x % 100);
x /= 100;
}
if x >= 10 {
two(x);
} else {
i -= 1;
*buf.add(i) = x as u8 + b'0';
}
i
}
#[macro_export]
macro_rules! out {
($out:expr, $($args:expr),*) => {{ $($out.output($args);)* }};
}
#[macro_export]
macro_rules! outln {
($out:expr) => { $out.ln(); };
($out:expr, $($args:expr),*) => {{
out!($out, $($args),*);
outln!($out);
}}
}
#[macro_export]
macro_rules! kdbg {
($($v:expr),*) => {
if cfg!(debug_assertions) { dbg!($($v),*) } else { ($($v),*) }
}
}
}
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