RT QAQ
by abcde777 @ 2021-05-27 11:18:14
@[abcde777](/user/341034) 树状数组的 `add` 没有 `return`，快读也写错了。
by 滑蒻稽 @ 2021-05-27 11:44:30
建议加上编译指令 `-Wall` 和 `-Wextra`
by 滑蒻稽 @ 2021-05-27 11:45:58
@[滑蒻稽](/user/113181) 确实是树状数组的问题，谢谢大佬QWQ
by abcde777 @ 2021-05-27 11:49:11
@[abcde777](/user/341034) 您比我强啊Orz，我学了3年还这么菜
by 滑蒻稽 @ 2021-05-27 11:51:47