RT，样例能过，下载了第一个数据点跟它的输出一模一样却全wa，不明白是为什么

#include<iostream>
#include<cstdio>
#include<cstring>

using namespace std;

long long n,m;
double a[100010];
double sum[400010],add[400010];
double ave[400010],s[400010];
struct node{
	double ll,summ;
	double av,ss;
};

void build(long long k,long long l,long long r) {
	if(l == r) {
		sum[k] = a[l];
		ave[k] = a[l];
		return;
	}
	long long mid = l+r>>1;
	build(k*2,l,mid);
	build(k*2+1,mid+1,r);
	sum[k] = sum[k*2] + sum[k*2+1];
	long long ls = mid-l+1,rs = r-mid,ll = r-l+1;
	ave[k] = sum[k] / (ll*1.0);
	s[k] = (double)ls*1.0/ll*(s[k*2] + (ave[k*2] - ave[k]) * (ave[k*2] - ave[k])) + (double)rs*1.0/ll*(s[k*2+1] + (ave[k*2+1] - ave[k]) * (ave[k*2+1] - ave[k]));
}

void Add(long long k,long long l,long long r,double v) {
	add[k] += v;
	sum[k] += (r-l+1) * v;
	ave[k] += v;
}

void pushdown(long long k,long long l,long long r,long long mid) {
	Add(k*2,l,mid,add[k]);
	Add(k*2+1,mid+1,r,add[k]);
	add[k] = 0;
}

void modify(long long k,long long l,long long r,long long x,long long y,double v) {
	if(l > y || r < x) return;
	if(l >= x && r <= y) return Add(k,l,r,v);
	long long mid = l+r>>1;
	pushdown(k,l,r,mid);
	modify(k*2,l,mid,x,y,v);
	modify(k*2+1,mid+1,r,x,y,v);
	sum[k] = sum[k*2] + sum[k*2+1];
	long long ls = mid-l+1,rs = r-mid,ll = r-l+1;
	ave[k] = sum[k] / (ll*1.0);
	s[k] = (double)ls*1.0/(ll*1.0)*(s[k*2] + (ave[k*2] - ave[k]) * (ave[k*2] - ave[k])) + (double)rs*1.0/ll*(s[k*2+1] + (ave[k*2+1] - ave[k]) * (ave[k*2+1] - ave[k]));
}

inline void pushup(node &res,const node &aa,const node &bb) {
	res.summ = aa.summ + bb.summ;
	res.ll = aa.ll + bb.ll;
	res.av = res.summ*1.0 / res.ll;
	res.ss = (double)aa.ll*1.0/res.ll*(aa.ss + (aa.av - res.av) * (aa.av - res.av)) + (double)bb.ll*1.0/res.ll*(bb.ss + (bb.av - res.av) * (bb.av - res.av));
}

node query(long long k,long long l,long long r,long long x,long long y) {
	if(l > y || r < x) {
		node res;
		res.summ = 0;
		res.ll = 0;
		res.av = 0;
		res.ss = 0;
		return res;
	}
	if(l >= x && r <= y) {
		node res;
		res.summ = sum[k];
		res.ll = r-l+1;
		res.av = ave[k];
		res.ss = s[k];
		return res;
	}
	long long mid = l+r>>1;
	pushdown(k,l,r,mid);
	node res;
	if(x <= mid && y >= mid) {
		pushup(res,query(k*2,l,mid,x,y),query(k*2+1,mid+1,r,x,y));
		return res;
	}
	else if(mid <= x && r >= x) res = query(k*2+1,mid+1,r,x,y);
	else if(mid >= y && l <= y) res = query(k*2,l,mid,x,y);
	return res;
}

int main() {
	cin >> n >> m;
	for(long long i = 1;i <= n;i++) {
		cin >> a[i];
	}
	build(1,1,n);
	
	for(long long i = 1;i <= m;i++) {
		long long t,x,y;
		double k;
		cin >> t;
		if(t == 1) {
			cin >> x >> y >> k;
			modify(1,1,n,x,y,k);
		}
		else if(t == 2) {
			cin >> x >> y;
			printf("%.4llf\n",query(1,1,n,x,y).av);
		}
		else {
			cin >> x >> y;
			printf("%.4llf\n",query(1,1,n,x,y).ss);
		}
	}
	
	return 0;
}