結果

問題 No.1300 Sum of Inversions
ユーザー phsplsphspls
提出日時 2022-11-17 11:08:19
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 273 ms / 2,000 ms
コード長 3,194 bytes
コンパイル時間 13,096 ms
コンパイル使用メモリ 380,408 KB
実行使用メモリ 26,240 KB
最終ジャッジ日時 2024-09-19 00:18:30
合計ジャッジ時間 22,222 ms
ジャッジサーバーID
（参考情報） 		judge3 / 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
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
コンパイルメッセージ
warning: field `orgn` is never read
 --> src/main.rs:7:5
  |
5 | struct SegmentTree<F, T> {
  |        ----------- field in this struct
6 |     n: usize,
7 |     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:29:8
   |
13 | / impl<F, T> SegmentTree<F, T> where
14 | | T: std::fmt::Debug + Copy,
15 | | F: Fn(T, T) -> T
   | |________________- methods in this implementation
...
29 |       fn find_closed(&self, l: usize, r: usize) -> T {
   |          ^^^^^^^^^^^
...
46 |       fn get(&mut self, pos: usize) -> T {
   |          ^^^

ソースコード

diff # 

const MOD: usize = 998244353;

#[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().unwrap()).collect();

    let mut orders = (0..n).collect::<Vec<_>>();
    orders.sort_by_key(|&i| a[i]);
    let mut maxvalseg = SegmentTree::new(n, 0usize, |x, y| x + y);
    let mut minvalseg = SegmentTree::new(n, 0usize, |x, y| x + y);
    let mut maxcntseg = SegmentTree::new(n, 0usize, |x, y| x + y);
    let mut mincntseg = SegmentTree::new(n, 0usize, |x, y| x + y);
    let mut leftvals = vec![0usize; n];
    let mut rightvals = vec![0usize; n];
    let mut leftcnts = vec![0usize; n];
    let mut rightcnts = vec![0usize; n];
    for &i in orders.iter() {
        rightvals[i] = minvalseg.find(i+1, n);
        rightcnts[i] = mincntseg.find(i+1, n);
        minvalseg.set(i, a[i]);
        mincntseg.set(i, 1);
    }
    for &i in orders.iter().rev() {
        leftvals[i] = maxvalseg.find(0, i);
        leftcnts[i] = maxcntseg.find(0, i);
        maxvalseg.set(i, a[i]);
        maxcntseg.set(i, 1);
    }
    let mut result = 0usize;
    for i in 0..n {
        let target = a[i];
        result += target * leftcnts[i] % MOD * rightcnts[i] % MOD;
        result += leftvals[i] * rightcnts[i] % MOD;
        result += rightvals[i] * leftcnts[i] % MOD;
        result %= MOD;
    }
    println!("{}", result);
}
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