提出 #18718882

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ソースコード 拡げる

use std::cmp::{max, min};

const MAX: usize = 300000;

fn main() {
    let (r, w) = (std::io::stdin(), std::io::stdout());
    let mut sc = IO::new(r.lock(), w.lock());
    let n: usize = sc.read();
    let k: usize = sc.read();
    let a: Vec<usize> = sc.vec(n);
    let mut seg = SegmentTree::new(MAX + 1, 0, max);
    for i in 0..n {
        let from = max(k, a[i]) - k;
        let to = min(MAX, a[i] + k);
        let t = seg.query(from..(to + 1));
        seg.update(a[i], t + 1);
    }
    let ans = seg.query(0..(MAX + 1));
    println!("{}", ans);
}

/// Segment Tree for range queries
pub struct SegmentTree<T, F> {
    seg: Vec<T>,
    n: usize,
    f: F,
    initial_value: T,
}

impl<T: Copy, F> SegmentTree<T, F>
where
    F: Fn(T, T) -> T,
{
    pub fn new(size: usize, initial_value: T, f: F) -> SegmentTree<T, F> {
        let mut m = 1;
        while m <= size {
            m <<= 1;
        }
        SegmentTree {
            seg: vec![initial_value; m * 2],
            n: m,
            f,
            initial_value,
        }
    }

    pub fn update(&mut self, k: usize, value: T) {
        let mut k = k;
        k += self.n - 1;
        self.seg[k] = value;
        while k > 0 {
            k = (k - 1) >> 1;
            self.seg[k] = (self.f)(self.seg[k * 2 + 1], self.seg[k * 2 + 2]);
        }
    }

    /// Get the minimum value in the array in the range
    pub fn query(&self, range: std::ops::Range<usize>) -> T {
        self.query_range(range, 0, 0..self.n)
    }

    fn query_range(
        &self,
        range: std::ops::Range<usize>,
        k: usize,
        seg_range: std::ops::Range<usize>,
    ) -> T {
        if seg_range.end <= range.start || range.end <= seg_range.start {
            self.initial_value
        } else if range.start <= seg_range.start && seg_range.end <= range.end {
            self.seg[k]
        } else {
            let mid = (seg_range.start + seg_range.end) >> 1;
            let x = self.query_range(range.clone(), k * 2 + 1, seg_range.start..mid);
            let y = self.query_range(range, k * 2 + 2, mid..seg_range.end);
            (self.f)(x, y)
        }
    }
}

pub struct IO<R, W: std::io::Write>(R, std::io::BufWriter<W>);

impl<R: std::io::Read, W: std::io::Write> IO<R, W> {
    pub fn new(r: R, w: W) -> Self {
        Self(r, std::io::BufWriter::new(w))
    }
    pub fn write<S: ToString>(&mut self, s: S) {
        use std::io::Write;
        self.1.write_all(s.to_string().as_bytes()).unwrap();
    }
    pub fn read<T: std::str::FromStr>(&mut self) -> T {
        use std::io::Read;
        let buf = self
            .0
            .by_ref()
            .bytes()
            .map(|b| b.unwrap())
            .skip_while(|&b| b == b' ' || b == b'\n' || b == b'\r' || b == b'\t')
            .take_while(|&b| b != b' ' && b != b'\n' && b != b'\r' && b != b'\t')
            .collect::<Vec<_>>();
        unsafe { std::str::from_utf8_unchecked(&buf) }
            .parse()
            .ok()
            .expect("Parse error.")
    }
    pub fn vec<T: std::str::FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.read()).collect()
    }
    pub fn chars(&mut self) -> Vec<char> {
        self.read::<String>().chars().collect()
    }
}

提出情報

ジャッジ結果