AtCoder Beginner Contest 417

AT_abc417_f [ABC417F] Random Gathering

少见的独立切出f
概率期望
对于每个[L,R]区间中的每个盘子
+1/len(sum - x )
或者
修改为 1/lens + (1-1/len)*0,发现就用区间查询区间修改就可以

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define pii pair<int,int>
#define ll long long
#define pb push_back
#define ft first
#define se second
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
#define ls(u) u<<1
#define rs(u) u<<1|1
// #define int long long

const int p = 998244353;
const int N = 200010;
int a[N];
struct Tree{
	int l, r;
	ll sum;
	int k;
}tr[4*N];

int qp(int a, int b){
	int res = 1;
	while(b){
		if(b & 1) res = 1ll* res * a % p;
		a = 1ll* a * a % p;
		b >>= 1; 
	}
	return res;
}

void pushup(int u){
	tr[u].sum = (tr[ls(u)].sum + tr[rs(u)].sum) % p;
}
void pushdown(int u){
	if(tr[u].k!= -1){
		tr[ls(u)].sum = 1ll*(tr[ls(u)].r - tr[ls(u)].l + 1) * tr[u].k %p;
		tr[ls(u)].k = tr[u].k;

		tr[rs(u)].sum = 1ll* (tr[rs(u)].r - tr[rs(u)].l + 1) * tr[u].k %p; 
		tr[rs(u)].k = tr[u].k;		

		tr[u].k = -1;
	}
}
void bui(int u, int l, int r){
	tr[u] = {l, r, a[l], -1};
	if(l == r){
		return ;
	}
	int mid = (l + r) >> 1;
	bui(u*2, l, mid);
	bui(u*2+1, mid + 1, r);
	pushup(u);
}
ll query(int u, int x, int y){
	if(x <= tr[u].l && tr[u].r <= y){
		return tr[u].sum;
	}
	int mid = (tr[u].l + tr[u].r) >> 1;
	pushdown(u);
	ll ret = 0;
	if(x <= mid) ret = (ret +  query(ls(u), x, y)%p )%p; 
	if(y >= mid + 1) ret = (ret +  query(rs(u), x, y)%p )%p;
	return ret;
}
void modify(int u, int x, int y, int k){
	if(x <= tr[u].l && tr[u].r <= y){
		tr[u].sum = 1ll* (tr[u].r - tr[u].l + 1) * k % p;
		tr[u].k = k;
		return ;
	}
	int mid = (tr[u].r + tr[u].l) >> 1;
	pushdown(u);
	if(x <= mid) modify(ls(u), x, y, k); 
	if(y >= mid + 1) modify(rs(u), x, y, k);
	pushup(u);
}

void solve(){
    int n, m;
	cin >> n >> m;
	for(int i = 1; i <= n; i ++) cin >> a[i];
	bui(1, 1, n);

	while(m --){
		int x, y; cin >> x >> y;
		ll s = query(1, x, y);
		modify(1, x, y, 1ll* qp(y - x + 1, p - 2) * s % p);
	}

	for(int i = 1; i <= n; i ++){
		cout << query(1, i, i) % p << ' ';
	}
}

signed main(){
    std::ios::sync_with_stdio(false);
    int T = 1; //cin >> T;
    while(T--){
        solve();
    }
}