結果

問題 No.2089 置換の符号
ユーザー phspls
提出日時 2022-10-01 11:29:43
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 4 ms / 2,000 ms
コード長 2,366 bytes
コンパイル時間 13,248 ms
コンパイル使用メモリ 405,236 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-12-23 16:10:07
合計ジャッジ時間 14,558 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge5
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ファイルパターン 結果
other AC * 33
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: unused variable: `v`
  --> src/main.rs:82:14
   |
82 |         let (v, idx) = a[i];
   |              ^ help: if this is intentional, prefix it with an underscore: `_v`
   |
   = note: `#[warn(unused_variables)]` on by default

warning: unused variable: `i`
  --> src/main.rs:78:25
   |
78 |     a.sort_by_key(|&(v, i)| v);
   |                         ^ help: if this is intentional, prefix it with an underscore: `_i`

warning: field `orgn` is never read
 --> src/main.rs:5:5
  |
3 | struct SegmentTree<F, T> {
  |        ----------- field in this struct
4 |     n: usize,
5 |     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: methods `find_closed` and `get` are never used
  --> src/main.rs:27:8
   |
11 | / impl<F, T> SegmentTree<F, T> where
12 | | T: std::fmt::Debug + Copy,
13 | | F: Fn(T, T) -> T
   | |________________- methods in this implementation
...
27 |       fn find_closed(&self, l: usize, r: usize) -> T {
   |          ^^^^^^^^^^^
...
44 |       fn get(&mut self, pos: usize) -> T {
   |          ^^^

ソースコード

diff # 

#[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 a: Vec<usize> = a.trim().split_whitespace().map(|s| s.parse::<usize>().unwrap()-1).collect();

    let mut a = (0..n).map(|i| (a[i], i)).collect::<Vec<(usize, usize)>>();
    a.sort_by_key(|&(v, i)| v);
    let mut segtree = SegmentTree::new(n, 0usize, |x, y| x + y);
    let mut result = 0usize;
    for i in (0..n).rev() {
        let (v, idx) = a[i];
        result += segtree.find(0, idx);
        segtree.set(idx, 1);
    }
    println!("{}", if result % 2 == 0 { 1 } else { -1 });
}
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