ural1855 Trade Guilds of Erathia

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <climits>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <list>
#define rep(i,m,n) for(i=m;i<=n;i++)
#define rsp(it,s) for(set<int>::iterator it=s.begin();it!=s.end();it++)
#define mod 1000000007
#define inf 0x3f3f3f3f
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ll long long
#define pi acos(-1.0)
#define pii pair<int,int>
#define Lson L, mid, rt<<1
#define Rson mid+1, R, rt<<1|1
const int maxn=1e5+10;
using namespace std;
ll gcd(ll p,ll q){return q==0?p:gcd(q,p%q);}
ll qpow(ll p,ll q){ll f=1;while(q){if(q&1)f=f*p;p=p*p;q>>=1;}return f;}
int n,m,k;
char op[10];
ll ans[3];
ll gao(int p)
{
    return (ll)p*(p+1)*(2*p+1)/6;
}
struct Node
{
    ll sum,sum1,sum2,lazy;
} T[maxn<<2];

void PushUp(int rt)
{
    T[rt].sum = T[rt<<1].sum + T[rt<<1|1].sum;
    T[rt].sum1 = T[rt<<1].sum1 + T[rt<<1|1].sum1;
    T[rt].sum2 = T[rt<<1].sum2 + T[rt<<1|1].sum2;
}

void PushDown(int L, int R, int rt)
{
    int mid = (L + R) >> 1;
    ll t = T[rt].lazy;

    T[rt<<1].sum += t * (mid - L + 1);
    T[rt<<1|1].sum += t * (R - mid);

    T[rt<<1].sum1 += t * (mid - L + 1)*(mid + L)/2;
    T[rt<<1|1].sum1 += t * (R - mid)*(R + mid +1)/2;

    T[rt<<1].sum2 += t * (gao(mid)-gao(L-1));
    T[rt<<1|1].sum2 += t * (gao(R)-gao(mid));

    T[rt<<1].lazy += t;
    T[rt<<1|1].lazy += t;
    T[rt].lazy = 0;
}

void Update(int l, int r, ll v, int L, int R, int rt)
{
    if(l==L && r==R)
    {
        T[rt].lazy += v;
        T[rt].sum += v * (R - L + 1);
        T[rt].sum1 += v * (R - L + 1)*(R + L)/2;
        T[rt].sum2 += v * (gao(R)-gao(L-1));
        return ;
    }
    int mid = (L + R) >> 1;
    if(T[rt].lazy) PushDown(L, R, rt);
    if(r <= mid) Update(l, r, v, Lson);
    else if(l > mid) Update(l, r, v, Rson);
    else
    {
        Update(l, mid, v, Lson);
        Update(mid+1, r, v, Rson);
    }
    PushUp(rt);
}

void Query(int l, int r, int L, int R, int rt)
{
    if(l==L && r== R)
    {
        ans[0]+=T[rt].sum;
        ans[1]+=T[rt].sum1;
        ans[2]+=T[rt].sum2;
        return;
    }
    int mid = (L + R) >> 1;
    if(T[rt].lazy) PushDown(L, R, rt);
    if(r <= mid) Query(l, r, Lson);
    else if(l > mid) Query(l, r, Rson);
    else Query(l, mid, Lson) , Query(mid + 1, r, Rson);
}
int main()
{
    int i,j;
    scanf("%d%d",&n,&m);
    while(m--)
    {
        int a,b,c;
        scanf("%s",op);
        if(op[0]==‘c‘)
        {
            scanf("%d%d%d",&a,&b,&c);
            Update(a+1,b,(ll)c,1,n,1);
        }
        else
        {
            scanf("%d%d",&a,&b);
            ans[0]=ans[1]=ans[2]=0;
            Query(a+1,b,1,n,1);
            printf("%.10f\n",(double)(-ans[2]+(a+b+1)*ans[1]-(a+(ll)a*b)*ans[0])/(b-a)/(b-a+1)*2);
        }
    }
    //system("Pause");
    return 0;
}