結果

問題 No.3122 Median of Medians of Division
ユーザー rhoo
提出日時 2025-05-26 00:15:31
言語 Rust
(1.83.0 + proconio)
結果
RE  
実行時間 -
コード長 6,431 bytes
コンパイル時間 14,064 ms
コンパイル使用メモリ 385,428 KB
実行使用メモリ 24,620 KB
最終ジャッジ日時 2025-05-26 00:15:52
合計ジャッジ時間 19,581 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
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ファイルパターン 結果
sample AC * 1
other AC * 13 RE * 27
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ソースコード

diff # 

#![allow(unused_imports,non_snake_case,dead_code)]
use std::{cmp::Reverse as Rev,collections::*,iter::*};
use proconio::{marker::*,*};


#[fastout]
fn main(){
    input!{
        n:usize,
        q:usize,
        mut a:[i64;n],
        qs:[(usize,usize,usize);q],
    }

    let get=|i:usize,a:&[i64]|->(i64,i64){
        let v0=*a.get(i).unwrap_or(&i64::MAX);
        let v1=*a.get(i+1).unwrap_or(&i64::MAX);

        (v0.min(v1),i64::MIN)
    };

    let mut seg={
        let a=(0..n-1).map(|i|get(i,&a)).collect::<Vec<_>>();
        Segtree::<S>::from(a)
    };

    for &(t,p,q) in &qs{
        if t==1{
            let (i,x)=(p-1,q as i64);
            a[i]=x;
            seg.set(i-1,get(i-1,&a));
            seg.set(i,get(i,&a));

        } else{
            let (l,r)=(p-1,q-1);

            let seg_max=seg.prod(l..r);

            let mut val=[seg_max.0,seg_max.1,a[l],a[r]];
            val.sort();
            val.reverse();

            let ans=val[1];
            println!("{ans}");

            // todo!();
        }
    }
}


struct S();


impl Monoid for S{
    type S=(i64,i64);
    fn identity()->(i64,i64){
        (i64::MIN,i64::MIN)
    }
    fn binary_operation(a:&(i64,i64),b:&(i64,i64))->(i64,i64){
        let mut a=*a;
        let mut b=*b;
        
        if a.0<=b.0{
            (a,b)=(b,a);
        }

        (a.0,a.1.max(b.0))
    }
}





fn ceil_pow2(n: u32) -> u32 {
    32 - n.saturating_sub(1).leading_zeros()
}


// TODO Should I split monoid-related traits to another module?
pub trait Monoid {
    type S: Clone;
    fn identity() -> Self::S;
    fn binary_operation(a: &Self::S, b: &Self::S) -> Self::S;
}


impl<M: Monoid> Default for Segtree<M> {
    fn default() -> Self {
        Segtree::new(0)
    }
}
impl<M: Monoid> Segtree<M> {
    pub fn new(n: usize) -> Segtree<M> {
        vec![M::identity(); n].into()
    }
}
impl<M: Monoid> From<Vec<M::S>> for Segtree<M> {
    fn from(v: Vec<M::S>) -> Self {
        let n = v.len();
        let log = ceil_pow2(n as u32) as usize;
        let size = 1 << log;
        let mut d = vec![M::identity(); 2 * size];
        d[size..(size + n)].clone_from_slice(&v);
        let mut ret = Segtree { n, size, log, d };
        for i in (1..size).rev() {
            ret.update(i);
        }
        ret
    }
}
impl<M: Monoid> Segtree<M> {
    pub fn set(&mut self, mut p: usize, x: M::S) {
        assert!(p < self.n);
        p += self.size;
        self.d[p] = x;
        for i in 1..=self.log {
            self.update(p >> i);
        }
    }

    pub fn get(&self, p: usize) -> M::S {
        assert!(p < self.n);
        self.d[p + self.size].clone()
    }

    pub fn prod<R>(&self, range: R) -> M::S
    where
        R: std::ops::RangeBounds<usize>,
    {
        // Trivial optimization
        if range.start_bound() == Bound::Unbounded && range.end_bound() == Bound::Unbounded {
            return self.all_prod();
        }

        let mut r = match range.end_bound() {
            Bound::Included(r) => r + 1,
            Bound::Excluded(r) => *r,
            Bound::Unbounded => self.n,
        };
        let mut l = match range.start_bound() {
            Bound::Included(l) => *l,
            Bound::Excluded(l) => l + 1,
            // TODO: There are another way of optimizing [0..r)
            Bound::Unbounded => 0,
        };

        assert!(l <= r && r <= self.n);
        let mut sml = M::identity();
        let mut smr = M::identity();
        l += self.size;
        r += self.size;

        while l < r {
            if l & 1 != 0 {
                sml = M::binary_operation(&sml, &self.d[l]);
                l += 1;
            }
            if r & 1 != 0 {
                r -= 1;
                smr = M::binary_operation(&self.d[r], &smr);
            }
            l >>= 1;
            r >>= 1;
        }

        M::binary_operation(&sml, &smr)
    }

    pub fn all_prod(&self) -> M::S {
        self.d[1].clone()
    }

    pub fn max_right<F>(&self, mut l: usize, f: F) -> usize
    where
        F: Fn(&M::S) -> bool,
    {
        assert!(l <= self.n);
        assert!(f(&M::identity()));
        if l == self.n {
            return self.n;
        }
        l += self.size;
        let mut sm = M::identity();
        while {
            // do
            while l % 2 == 0 {
                l >>= 1;
            }
            if !f(&M::binary_operation(&sm, &self.d[l])) {
                while l < self.size {
                    l *= 2;
                    let res = M::binary_operation(&sm, &self.d[l]);
                    if f(&res) {
                        sm = res;
                        l += 1;
                    }
                }
                return l - self.size;
            }
            sm = M::binary_operation(&sm, &self.d[l]);
            l += 1;
            // while
            {
                let l = l as isize;
                (l & -l) != l
            }
        } {}
        self.n
    }

    pub fn min_left<F>(&self, mut r: usize, f: F) -> usize
    where
        F: Fn(&M::S) -> bool,
    {
        assert!(r <= self.n);
        assert!(f(&M::identity()));
        if r == 0 {
            return 0;
        }
        r += self.size;
        let mut sm = M::identity();
        while {
            // do
            r -= 1;
            while r > 1 && r % 2 == 1 {
                r >>= 1;
            }
            if !f(&M::binary_operation(&self.d[r], &sm)) {
                while r < self.size {
                    r = 2 * r + 1;
                    let res = M::binary_operation(&self.d[r], &sm);
                    if f(&res) {
                        sm = res;
                        r -= 1;
                    }
                }
                return r + 1 - self.size;
            }
            sm = M::binary_operation(&self.d[r], &sm);
            // while
            {
                let r = r as isize;
                (r & -r) != r
            }
        } {}
        0
    }

    fn update(&mut self, k: usize) {
        self.d[k] = M::binary_operation(&self.d[2 * k], &self.d[2 * k + 1]);
    }
}

// Maybe we can use this someday
// ```
// for i in 0..=self.log {
//     for j in 0..1 << i {
//         print!("{}\t", self.d[(1 << i) + j]);
//     }
//     println!();
// }
// ```

struct Segtree<M>
where
    M: Monoid,
{
    // variable name is _n in original library
    n: usize,
    size: usize,
    log: usize,
    d: Vec<M::S>,
}
0