线段树模板

#include<bits/stdc++.h>
using namespace std;
int a[1000005];
int sum[1000005*4];
int lazy[1000005*4];
int n,m;
void push_down(int rt,int l,int r)
{
    if(lazy[rt]!=0)
    {
        int mid=(l+r)>>1;
        lazy[2*rt]+=lazy[rt];
        lazy[2*rt+1]+=lazy[rt];
        sum[2*rt]+=(mid-l+1)*lazy[rt];
        sum[2*rt+1]+=(r-mid)*lazy[rt];
        lazy[rt]=0;
    }
}
void build(int l,int r,int rt)
{
    if(l==r)
    {
        sum[rt]=a[l];
        return ;
    }
    int mid=(l+r)/2;
    build(l,mid,2*rt);
    build(mid+1,r,2*rt+1);
    sum[rt]=sum[2*rt]+sum[2*rt+1];
    return ;
}
int query(int L,int R,int l,int r,int rt)
{
    if(L<=l&&r<=R)
    return sum[rt];
    push_down(rt,L,R);
    int mid=(l+r)/2;
    int ans=0;
    if(L<=mid)
    ans+=query(L,R,l,mid,2*rt);
    if(R>mid)
    ans+=query(L,R,mid+1,r,2*rt+1);
    return ans;
}
void mo(int rt,int L,int R,int l,int r,int k)
{
    if(L<=l&&r<=R)
    {
        sum[rt]+=(r-l+1)*k;
        lazy[rt]+=k;
        return ;
    }
    push_down(rt,l,r);
    int mid=(l+r)/2;
    if(L<=mid)
    {
        mo(2*rt,L,R,l,mid,k);
    }
    if(R>mid)
    {
        mo(2*rt+1,L,R,mid+1,r,k);
    }
    sum[rt]=sum[2*rt]+sum[2*rt+1];
    return ;
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    build(1,n,1);
    while(m--)
    {
        int op;
        cin>>op;
        if(op==1)
        {
            int a,b,c;
            cin>>a>>b>>c;
            mo(1,a,b,1,n,c);
        }
        else
        {
            int a,b;
            cin>>a>>b;
            cout<<query(a,b,1,n,1)<<endl;
        }
    }
    return 0;
}