HDU7059 Counting Stars

传送门


这题贼简单,结果线段树竟然写错了,奇耻大辱。


由题意得,每一个数的'1'的个数只减不增,那么最多只会改31次,因此对于删除lowbit的操作,可以暴力修改,时间复杂度\(O(nlog^2n)\)。

而对于第二种操作,只是相当于把最高位的'1'往高挪了一位,那么用线段树维护区间最高位的和,以及向左移动多少位的标记。区间修改的时候就将标记+1,并且区间和加上最高位的和,最高位的和再乘以2即可。

#include<bits/stdc++.h>
using namespace std;
#define enter puts("")
#define space putchar(' ')
#define Mem(a, x) memset(a, x, sizeof(a))
#define In inline
typedef long long ll;
const int maxn = 1e5 + 5;
const ll mod = 998244353;
const int N = 30;
In ll read() {ll x; scanf("%lld", &x); return x;}
In void write(ll x) {printf("%lld", x);}

ll q2[maxn];
In ll ADD(const ll& a, const ll& b) {return a + b < mod ? a + b : a + b - mod;}

int n, Q;
ll a[maxn];

struct Tree
{
	int l, r;
	ll sum, rsum, lzy;
	bool lft;
	In Tree operator + (const Tree& oth)const
	{
		Tree ret; ret.l = l, ret.r = oth.r;
		ret.sum = ADD(sum, oth.sum);
		ret.rsum = ADD(rsum, oth.rsum);
		ret.lzy = 0;
		ret.lft = lft | oth.lft;
		return ret;
	}
}t[maxn << 2];
In void build(int L, int R, int now)
{
	t[now].l = L, t[now].r = R;
	if(L == R)
	{
		a[L] = read();
		t[now].sum = a[L] % mod, t[now].lzy = 0;
		t[now].rsum = 0;
		if(a[L]) t[now].lft = 1;
		for(int i = N; i >= 0; --i)
			if((a[L] >> i) & 1) 
			{
				t[now].rsum = (1 << i) % mod;
				break;
			}
		return;
	}
	int mid = (L + R) >> 1;
	build(L, mid, now << 1), build(mid + 1, R, now << 1 | 1);
	t[now] = t[now << 1] + t[now << 1 | 1];
}
In void Change(int now, int d)
{
	ll tp = q2[d];
	t[now].sum = ADD(t[now].sum, t[now].rsum * (tp - 1 + mod) % mod);
	t[now].rsum = t[now].rsum * tp % mod;
	t[now].lzy += d;
}
In void pushdown(int now)
{
	if(t[now].lzy)
	{
		Change(now << 1, t[now].lzy), Change(now << 1 | 1, t[now].lzy);
		t[now].lzy = 0;
	}
}
In void update_low(int L, int R, int now)
{
	if(!t[now].lft) return;		//整个区间都是0了 
	if(t[now].l == t[now].r)	//我竟然写成L == R,而且整场比赛没看出来 
	{
		ll tp = a[L] & (-a[L]);
		if(tp == a[L])
		{
			t[now].rsum = t[now].sum = 0;
			t[now].lzy = t[now].lft = 0;
		}
		else
		{
			t[now].sum = ADD(t[now].sum, mod- tp % mod);
			a[L] -= tp;
		}
		return;
	}
	pushdown(now);
	int mid = (t[now].l + t[now].r) >> 1;
	if(R <= mid) update_low(L, R, now << 1);
	else if(L > mid) update_low(L, R, now << 1 | 1);
	else update_low(L, mid, now << 1), update_low(mid + 1, R, now << 1 | 1);
	t[now] = t[now << 1] + t[now << 1 | 1];
}
In void update_hig(int L, int R, int now)
{
	if(t[now].l == L && t[now].r == R)
	{
		Change(now, 1);
		return;
	}
	pushdown(now);
	int mid = (t[now].l + t[now].r) >> 1;
	if(R <= mid) update_hig(L, R, now << 1);
	else if(L > mid) update_hig(L, R, now << 1 | 1);
	else update_hig(L, mid, now << 1), update_hig(mid + 1, R, now << 1 | 1);
	t[now] = t[now << 1] + t[now << 1 | 1];
}
In ll query(int L, int R, int now)
{
	if(t[now].l == L && t[now].r == R) return t[now].sum;
	pushdown(now);
	int mid = (t[now].l + t[now].r) >> 1;
	if(R <= mid) return query(L, R, now << 1);
	else if(L > mid) return query(L, R, now << 1 |1);
	else return ADD(query(L, mid, now << 1), query(mid + 1, R, now << 1 | 1));
}

int main()
{
	int T = read();
	q2[0] = 1;
	for(int i = 1; i < maxn; ++i) q2[i] = q2[i - 1] * 2 % mod;
	while(T--)
	{
		n = read();
		build(1, n, 1);
		Q = read();
		for(int i = 1; i <= Q; ++i)
		{
			int op = read(), L = read(), R = read();
			if(L > R) swap(L, R);
			if(op == 1) write(query(L, R, 1)), enter;
			else if(op == 2) update_low(L, R, 1);
			else update_hig(L, R, 1);
		}
	}
	return 0;
}
上一篇:A - Stars


下一篇:【题解】CF1559E Mocha and Stars