线段树

const int N=200005;  
struct Node{  
    int l,r,sum;  
}tree[N];  
  
int a[N];  
  
char opr[10]; //操作数组  
void build(int index,int l,int r){ //建树  
    tree[index].l=l;  
    tree[index].r=r;  
    if(l==r){  
        tree[index].sum=a[l];     
        return;  
    }  
    build(2*index,l,(r+l)/2);  
    build(2*index+1,(r+l)/2+1,r);  
      
    tree[index].sum=tree[2*index].sum+tree[2*index+1].sum;  
}  
  
void update(int index,int i,int j){ //更新树  
    tree[index].sum+=j;  
  
    if(tree[index].l==i&&tree[index].r==i){  
        return;  
    }  
    int mid=(tree[index].l+tree[index].r)/2;  
      
    if(i>mid){  
        update(2*index+1,i,j);  
    }  
    else{  
        update(2*index,i,j);  
    }  
}  
  
int query(int index,int i,int j){  //查询  
      
    if(tree[index].l==i&&tree[index].r==j){  
        return tree[index].sum;  
    }  
    int mid=(tree[index].l+tree[index].r)/2;  
    if(i>mid){  
        return query(2*index+1,i,j);  
    }  
    else if(j<=mid){  
        return query(2*index,i,j);  
    }  
    else{  
        return query(2*index,i,mid)+query(2*index+1,mid+1,j);  
    }  
}