【POJ】3468 A Simple Problem with Integers

#include<cstdio>
typedef __int64 LL;
#define MAXN 100010
LL tree[MAXN<<2],lazy[MAXN<<2];
inline void PushUp(int rt)
{
    tree[rt]=tree[rt<<1]+tree[rt<<1|1];
}
void Build(int L,int R,int rt)
{
    lazy[rt]=0;
    if(L==R)
        scanf("%I64d",&tree[rt]);
    else
    {
        int mid=(L+R)>>1;
        Build(L,mid,rt<<1);
        Build(mid+1,R,rt<<1|1);
        PushUp(rt);
    }
}
inline void PushDown(int mid,int L,int R,int rt)
{
    if(lazy[rt])
    {
        lazy[rt<<1]+=lazy[rt];
        lazy[rt<<1|1]+=lazy[rt];
        tree[rt<<1]+=(mid-L+1)*lazy[rt];
        tree[rt<<1|1]+=(R-mid)*lazy[rt];
        lazy[rt]=0;
    }
}
LL Query(int x,int y,int L,int R,int rt)
{
    if(x<=L&&R<=y)
        return tree[rt];
    int mid=(L+R)>>1;
    LL ans=0;
    PushDown(mid,L,R,rt);
    if(mid>=x)
        ans+=Query(x,y,L,mid,rt<<1);
    if(y>mid)
        ans+=Query(x,y,mid+1,R,rt<<1|1);
    return ans;
}
void Update(int x,int y,int z,int L,int R,int rt)
{
    if(x<=L&&R<=y)
    {
        lazy[rt]+=z;
        tree[rt]+=(LL)(R-L+1)*z;
    }
    else
    {
        int mid=(L+R)>>1;
        PushDown(mid,L,R,rt);
        if(mid>=x)
            Update(x,y,z,L,mid,rt<<1);
        if(y>mid)
            Update(x,y,z,mid+1,R,rt<<1|1);
        PushUp(rt);
    }
}
int main()
{
    char ch;
    int n,q,a,b,c;
    while(~scanf("%d%d",&n,&q))
    {
        Build(1,n,1);
        while(q--)
        {
            scanf(" %c",&ch);
            if(ch=='Q')
            {
                scanf("%d%d",&a,&b);
                printf("%I64d\n",Query(a,b,1,n,1));
            }
            else
            {
                scanf("%d%d%d",&a,&b,&c);
                Update(a,b,c,1,n,1);
            }
        }
    }
    return 0;
}