結果

問題 No.1282 Display Elements
コンテスト
ユーザー phspls
提出日時 2022-11-14 11:38:26
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 91 ms / 2,000 ms
コード長 2,832 bytes
コンパイル時間 24,624 ms
コンパイル使用メモリ 382,716 KB
実行使用メモリ 16,480 KB
最終ジャッジ日時 2024-09-15 13:45:41
合計ジャッジ時間 23,297 ms
ジャッジサーバーID
（参考情報） 		judge6 / judge1
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
other AC * 24
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:76:9
   |
76 |     let mut a: Vec<usize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
   |         ----^
   |         |
   |         help: remove this `mut`
   |
   = note: `#[warn(unused_mut)]` on by default

warning: field `orgn` is never read
 --> src/main.rs:6:5
  |
4 | struct SegmentTree<F, T> {
  |        ----------- field in this struct
5 |     n: usize,
6 |     orgn: usize,
  |     ^^^^
  |
  = note: `SegmentTree` has derived impls for the traits `Clone` and `Debug`, but these are intentionally ignored during dead code analysis
  = note: `#[warn(dead_code)]` on by default

warning: method `find_closed` is never used
  --> src/main.rs:28:8
   |
12 | / impl<F, T> SegmentTree<F, T> where
13 | | T: std::fmt::Debug + Copy,
14 | | F: Fn(T, T) -> T
   | |________________- method in this implementation
...
28 |       fn find_closed(&self, l: usize, r: usize) -> T {
   |          ^^^^^^^^^^^

ソースコード

diff #
raw source code 

use std::collections::{BTreeSet, HashMap};

#[derive(Debug, Clone)]
struct SegmentTree<F, T> {
    n: usize,
    orgn: usize,
    unit: T,
    mem: Vec<T>,
    operator: F
}

impl<F, T> SegmentTree<F, T> where
T: std::fmt::Debug + Copy,
F: Fn(T, T) -> T
{
    fn new(n: usize, unit: T, operator: F) -> Self {
        let mut size = 1usize;
        while size < n { size *= 2; }
        Self {
            n: size,
            orgn: n,
            unit: unit,
            mem: vec![unit; size*2-1],
            operator: operator,
        }
    }

    fn find_closed(&self, l: usize, r: usize) -> T {
        self.find(l, r+1)
    }

    fn find(&self, l: usize, r: usize) -> T {
        self._find(l, r, 0, 0, self.n)
    }

    fn set(&mut self, pos: usize, val: T) {
        let mut pos = pos + self.n - 1;
        self.mem[pos] = val;
        while pos > 0 {
            pos = self._parent(pos);
            self.mem[pos] = (self.operator)(self.mem[self._left(pos)], self.mem[self._right(pos)]);
        }
    }

    fn get(&mut self, pos: usize) -> T {
        self.mem[pos + self.n - 1]
    }

    fn _find(&self, a: usize, b: usize, nodenum: usize, l: usize, r: usize) -> T {
        if r <= a || b <= l {
            return self.unit;
        } else if a <= l && r <= b {
            return self.mem[nodenum];
        }
        let left = self._find(a, b, self._left(nodenum), l, (l+r)/2);
        let right = self._find(a, b, self._right(nodenum), (l+r)/2, r);
        (self.operator)(left, right)
    }
    fn _left(&self, k: usize) -> usize {
        2*k+1
    }
    fn _right(&self, k: usize) -> usize {
        2*k+2
    }
    fn _parent(&self, k: usize) -> usize {
        (k-1)/2
    }
}

fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let mut a: Vec<usize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let mut b = String::new();
    std::io::stdin().read_line(&mut b).ok();
    let b: Vec<usize> = b.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let mut vals = a.iter().copied().collect::<BTreeSet<_>>();
    for &v in b.iter() { vals.insert(v); }
    let mapping = vals.iter().enumerate().map(|(i, &v)| (v, i)).collect::<HashMap<usize, usize>>();
    let mut a = a.into_iter().map(|v| *mapping.get(&v).unwrap()).collect::<Vec<_>>();
    let b = b.into_iter().map(|v| *mapping.get(&v).unwrap()).collect::<Vec<_>>();
    a.sort();
    let mut segtree = SegmentTree::new(vals.len(), 0usize, |x, y| x+y);
    let mut result = 0usize;
    for i in 0..n {
        let val = segtree.get(b[i]);
        segtree.set(b[i], val+1);
        result += segtree.find(0, a[i]);
    }
    println!("{}", result);
}
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