loj2005 「SDOI2017」相关分析

鬼畜线段树……Orz Capella

#include <iostream>
#include <cstdio>
using namespace std;
int n, m, uu, vv, opt;
double xx[100005], yy[100005], ss, tt, faq[4];
struct SGT{
	double val[400005][4], stag[400005], ttag[400005];
	/*
	 * val[0]: x_i^2
	 * val[1]: x_i
	 * val[2]: y_i
	 * val[3]: x_i*y_i
	 */
	bool ismo[400005];
	void pushUp(int o, int lson, int rson){
		for(int i=0; i<4; i++)
			val[o][i] = val[lson][i] + val[rson][i];
	}
	double calc(int x){
		return (double)x*(x+1)*(2*x+1)/6.0;
	}
	void pushModify(int o, int l, int r){
		val[o][0] = val[o][3] = calc(r) - calc(l-1);
		val[o][1] = val[o][2] = (double)(l+r) * (r-l+1) / 2.0;
		ismo[o] = true;
		stag[o] = ttag[o] = 0.0;
	}
	void pushAdd(int o, int l, int r, double s, double t){
		int siz=r-l+1;
		val[o][0] += 2.0*s*val[o][1] + s*s*siz;
		val[o][3] += s*val[o][2] + t*val[o][1] + s*t*siz;
		val[o][1] += s * siz;
		val[o][2] += t * siz;
		stag[o] += s;
		ttag[o] += t;
	}
	void pushDown(int o, int l, int r, int lson, int rson, int mid){
		if(ismo[o]){
			if(l<=mid)	pushModify(lson, l, mid);
			if(mid<r)	pushModify(rson, mid+1, r);
		}
		if(l<=mid)	pushAdd(lson, l, mid, stag[o], ttag[o]);
		if(mid<r)	pushAdd(rson, mid+1, r, stag[o], ttag[o]);
		stag[o] = ttag[o] = ismo[o] = 0;
	}
	void build(int o, int l, int r){
		if(l==r){
			val[o][0] = xx[l] * xx[l];
			val[o][1] = xx[l]; val[o][2] = yy[l];
			val[o][3] = xx[l] * yy[l];
		}
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			if(l<=mid)	build(lson, l, mid);
			if(mid<r)	build(rson, mid+1, r);
			pushUp(o, lson, rson);
		}
	}
	void update(int o, int l, int r, int x, int y, double s, double t){
		// printf("faQ\n");
		if(l>=x && r<=y)	pushAdd(o, l, r, s, t);
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			pushDown(o, l, r, lson, rson, mid);
			if(x<=mid)	update(lson, l, mid, x, y, s, t);
			if(mid<y)	update(rson, mid+1, r, x, y, s, t);
			pushUp(o, lson, rson);
		}
	}
	void modify(int o, int l, int r, int x, int y, double s, double t){
		if(l>=x && r<=y){
			pushModify(o, l, r);
			pushAdd(o, l, r, s, t);
		}
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			pushDown(o, l, r, lson, rson, mid);
			if(x<=mid)	modify(lson, l, mid, x, y, s, t);
			if(mid<y)	modify(rson, mid+1, r, x, y, s, t);
			pushUp(o, lson, rson);
		}
	}
	void query(int o, int l, int r, int x, int y){
		if(l>=x && r<=y){
			for(int i=0; i<4; i++)
				faq[i] += val[o][i];
		}
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			pushDown(o, l, r, lson, rson, mid);
			if(x<=mid)	query(lson, l, mid, x, y);
			if(mid<y)	query(rson, mid+1, r, x, y);
		}
	}
}sgt;
double queryRange(int l, int r){
	for(int i=0; i<4; i++)	faq[i] = 0.0;
	sgt.query(1, 1, n, l, r);
	return (faq[3]-faq[1]*faq[2]/(r-l+1)) / (faq[0]-faq[1]*faq[1]/(r-l+1));
}
int main(){
	cin>>n>>m;
	for(int i=1; i<=n; i++)
		scanf("%lf", &xx[i]);
	for(int i=1; i<=n; i++)
		scanf("%lf", &yy[i]);
	sgt.build(1, 1, n);
	while(m--){
		scanf("%d", &opt);
		if(opt==1){
			scanf("%d %d", &uu, &vv);
			printf("%.10f\n", queryRange(uu, vv));
		}
		else if(opt==2){
			scanf("%d %d %lf %lf", &uu, &vv, &ss, &tt);
			sgt.update(1, 1, n, uu, vv, ss, tt);
		}
		else{
			scanf("%d %d %lf %lf", &uu, &vv, &ss, &tt);
			sgt.modify(1, 1, n, uu, vv, ss, tt);
		}
	}
	return 0;
}