看看是不是你 $add$ 函数里面 ```tree[id].sum+=(tree[id].r-tree[id].l)*k;```这一句，改成```tree[id].sum+=(tree[id].r-tree[id].l+1)*k;```试试看
by Mr_HY43205 @ 2021-07-28 23:38:22
@[Mr_HY43205](/user/362761) 谢谢大佬
by 虫洞吞噬者 @ 2021-07-30 10:40:54
@[虫洞吞噬者](/user/159959) 对了吗
by Mr_HY43205 @ 2021-07-30 10:54:43
@[Mr_HY43205](/user/362761) 对了。最近在复健，可能出了许多伞兵错误
by 虫洞吞噬者 @ 2021-07-30 17:51:11