1 #include
     
       2 #include
      
        3 #define MAXN 50010 4 int tree[MAXN<<2]; 5 inline void PushUp(int rt) 6 { 7     tree[rt]=tree[rt<<1]+tree[rt<<1|1]; 8 } 9 void Build(int L,int R,int rt)10 {11     if(L==R)12         scanf("%d",&tree[rt]);13     else14     {15         int mid=(L+R)>>1;16         Build(L,mid,rt<<1);17         Build(mid+1,R,rt<<1|1);18         PushUp(rt);19     }20 }21 void Update(int x,int val,int L,int R,int rt)22 {23     if(L==R)24         tree[rt]+=val;25     else26     {27         int mid=(L+R)>>1;28         if(x<=mid)29             Update(x,val,L,mid,rt<<1);30         else31             Update(x,val,mid+1,R,rt<<1|1);32         PushUp(rt);33     }34 }35 int Query(int x,int y,int L,int R,int rt)36 {37     if(x<=L&&R<=y)38         return tree[rt];39     int mid,ans;40     mid=(L+R)>>1;41     ans=0;42     if(mid>=x)43         ans+=Query(x,y,L,mid,rt<<1);44     if(mid