結果

問題 No.2601 Very Poor
ユーザー naut3
提出日時 2024-01-12 21:45:04
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 346 ms / 2,000 ms
コード長 5,192 bytes
コンパイル時間 11,097 ms
コンパイル使用メモリ 379,040 KB
実行使用メモリ 14,372 KB
最終ジャッジ日時 2024-09-30 06:20:08
合計ジャッジ時間 19,241 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge1
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ファイルパターン 結果
sample AC * 3
other AC * 34
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 # 

#![allow(non_snake_case, unused_imports, unused_must_use)]
use std::io::{self, prelude::*};
use std::str;

fn main() {
    let (stdin, stdout) = (io::stdin(), io::stdout());
    let mut scan = Scanner::new(stdin.lock());
    let mut out = io::BufWriter::new(stdout.lock());

    macro_rules! input {
        ($T: ty) => {
            scan.token::<$T>()
        };
        ($T: ty, $N: expr) => {
            (0..$N).map(|_| scan.token::<$T>()).collect::<Vec<_>>()
        };
    }

    let N = input!(usize);
    let X = input!(usize);
    let mut A = input!(usize, N);

    let B = {
        let mut a = vec![];
        a.append(&mut A.clone());
        a.append(&mut A);
        a
    };

    let stree = SegmentTree::from(&B, |x, y| x + y, 0);

    let mut ans = 0;

    for i in 0..N {
        let mut ok = 0;
        let mut ng = N + 1;

        while ng - ok > 1 {
            let m = (ok + ng) / 2;

            if stree.prod(i..i + m) > X {
                ng = m;
            } else {
                ok = m;
            }
        }

        ans = std::cmp::max(ans, stree.prod(i..i + ok));
    }

    writeln!(out, "{}", ans);
}

struct Scanner<R> {
    reader: R,
    buf_str: Vec<u8>,
    buf_iter: str::SplitWhitespace<'static>,
}
impl<R: BufRead> Scanner<R> {
    fn new(reader: R) -> Self {
        Self {
            reader,
            buf_str: vec![],
            buf_iter: "".split_whitespace(),
        }
    }
    fn token<T: str::FromStr>(&mut self) -> T {
        loop {
            if let Some(token) = self.buf_iter.next() {
                return token.parse().ok().expect("Failed parse");
            }
            self.buf_str.clear();
            self.reader
                .read_until(b'\n', &mut self.buf_str)
                .expect("Failed read");
            self.buf_iter = unsafe {
                let slice = str::from_utf8_unchecked(&self.buf_str);
                std::mem::transmute(slice.split_whitespace())
            }
        }
    }
}

pub struct SegmentTree<M> {
    size: usize,
    tree: Vec<M>,
    op: fn(&M, &M) -> M,
    id: M,
}

impl<M: Copy + PartialEq> SegmentTree<M> {
    /// self.tree = [id; size], self.op = op, self.id = id
    pub fn new(size: usize, op: fn(&M, &M) -> M, id: M) -> Self {
        return Self {
            size: size,
            tree: vec![id; 2 * size],
            op: op,
            id: id,
        };
    }

    /// self.tree = arr, self.op = op, self.id = id
    pub fn from(arr: &[M], op: fn(&M, &M) -> M, id: M) -> Self {
        let size = arr.len();
        let mut tree = vec![id; 2 * size];

        for i in 0..size {
            tree[i + size] = arr[i];

            assert!(
                op(&id, &arr[i]) == arr[i],
                "id is not the identity element of given operator"
            );
        }

        for i in (1..size).rev() {
            tree[i] = op(&tree[i << 1], &tree[i << 1 | 1]);
        }

        return Self {
            size: size,
            tree: tree,
            op: op,
            id: id,
        };
    }

    /// self.tree[pos] <- value
    pub fn insert(&mut self, mut pos: usize, value: M) -> () {
        pos += self.size;
        self.tree[pos] = value;

        while pos > 1 {
            pos >>= 1;
            self.tree[pos] = (self.op)(&self.tree[pos << 1], &self.tree[pos << 1 | 1]);
        }
    }

    /// return self.tree[pos] (syntax sugar: self[pos])
    pub fn get_point(&self, pos: usize) -> M {
        return self[pos];
    }

    /// return Π_{i ∈ [left, right)} self.tree[i]
    pub fn get(&self, left: usize, right: usize) -> M {
        let (mut l, mut r) = (left + self.size, right + self.size);
        let (mut vl, mut vr) = (self.id, self.id);

        while l < r {
            if l & 1 == 1 {
                vl = (self.op)(&vl, &self.tree[l]);
                l += 1;
            }

            if r & 1 == 1 {
                r -= 1;
                vr = (self.op)(&self.tree[r], &vr);
            }

            l >>= 1;
            r >>= 1;
        }

        return (self.op)(&vl, &vr);
    }

    /// return Π_{i ∈ range} self.tree[i]
    pub fn prod<R: std::ops::RangeBounds<usize>>(&self, range: R) -> M {
        let left = match range.start_bound() {
            std::ops::Bound::Included(&l) => l,
            std::ops::Bound::Excluded(&l) => l + 1,
            std::ops::Bound::Unbounded => 0,
        };

        let right = match range.end_bound() {
            std::ops::Bound::Included(&r) => r + 1,
            std::ops::Bound::Excluded(&r) => r,
            std::ops::Bound::Unbounded => self.size,
        };

        return self.get(left, right);
    }
}

impl<M> std::ops::Index<usize> for SegmentTree<M> {
    type Output = M;
    fn index(&self, index: usize) -> &Self::Output {
        &self.tree[index + self.size]
    }
}

impl<M: std::fmt::Display> std::fmt::Display for SegmentTree<M> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}",
            self.tree[self.size..]
                .iter()
                .map(|x| x.to_string())
                .collect::<Vec<_>>()
                .join(" ")
        )
    }
}
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