c++ - Spoj - 使用线段树很糟糕

Question

我得到了不正确的问题可怕的结果

这是我的代码：http: //ideone.com/1Yb3yp

node query(int root,int l_most,int r_most,int l,int r)
{
  if(l_most >= l && r_most <= r)
    return tree[root];
  int l_child = (root<<1) , r_child = l_child + 1,mid = (l_most + r_most )>>1;
  node left=node(),right = node();
  if(l<=mid)
    left = query(l_child,l_most,mid,l,r);
  if(r>mid)
    right = query(r_child,mid+1,r_most,l,r);;
  node temp = node();
  temp.merge(left,right);
  return temp;
}