洛谷P1502 窗口的星星

题链

扫描线模板题

将每个星星扩展为一个矩形，长w-1，宽h-1，扩展的长度不同维护的东西也不同。

这样扩展结果是维护一个个点，如图

而后维护区间max，操作只有区间加减。

#include <bits/stdc++.h>
#include <ext/pb_ds/priority_queue.hpp>
//#pragma GCC optimize("O2")
using namespace std;
using namespace __gnu_pbds;
#define Pair pair<LL,LL>
#define Combine Pair, greater<Pair>, pairing_heap_tag
#define LL long long
#define ll long long
#define ULL unsigned long long
#define ls rt<<1
#define rs rt<<1|1
#define one first
#define two second
#define MS 1000009
#define INF 1e18
#define DBINF 1e100
#define Pi acos(-1.0)
#define eps 1e-9
#define mod 99999997

LL n,m;
LL w,h;
struct node{
	LL xl,xr,y,g;
}line[MS*2];
LL hx[MS*2]; 
LL p[MS<<3];
LL la[MS<<3];
LL tli,thx;

bool cmp(node a,node b){
	if(a.y == b.y) return a.g > b.g;
	return a.y < b.y;
}

void push_down(int rt){
	if(la[rt]){
		p[ls] += la[rt];
		p[rs] += la[rt];
		la[ls] += la[rt];
		la[rs] += la[rt];
		la[rt] = 0;
	} 
}

void push_up(int rt,int l,int r){
	p[rt] = max(p[ls],p[rs]);
}

void build(int l,int r,int rt){
	la[rt] = p[rt] = 0;
	if(l == r) return;
	int m = l+r>>1;
	build(l,m,ls);
	build(m+1,r,rs);
}

void update(int L,int R,int l,int r,int rt,LL val){
	if(L <= l && r <= R){
		la[rt] += val;
		p[rt] += val;
		return;
	}
	int m = l+r>>1;
	push_down(rt);
	if(m >= L) update(L,R,l,m,ls,val);
	if(m <  R) update(L,R,m+1,r,rs,val);
	push_up(rt,l,r); 
}

int main() {
	ios::sync_with_stdio(false);
	LL ce;
	cin >> ce;
	while(ce--){
		thx = 0;
		tli = 0;
		cin >> n >> w >> h;
		w-- ,h--;
		for(int i=1;i<=n;i++){
			LL x,y,g;
			cin >> x >> y >> g;
			hx[++tli] = x;
			line[tli] = {x,x+w,y,g};
			hx[++tli] = x+w;
			line[tli] = {x,x+w,y+h,-g};
		}
		sort(hx+1,hx+tli+1);
		sort(line+1,line+tli+1,cmp);
		thx = 1;
		for(int i=2;i<=tli;i++){
			if(hx[i] != hx[i-1]) hx[++thx] = hx[i];
		}
		build(1,thx,1);
		LL ans = 0;
		for(int i=1;i<=tli;i++){
			int l = lower_bound(hx+1,hx+thx+1,line[i].xl) - hx;
			int r = lower_bound(hx+1,hx+thx+1,line[i].xr) - hx;
			update(l,r,1,thx,1,line[i].g);
			ans = max(ans,p[1]);
		}
		cout << ans << endl;
	}
	



	return 0;

}