Today when I took part in the Round #740 solving problem [D. Top-Notch Insertions](https://mirror.codeforces.com/contest/1558/problem/D), [my submission](https://mirror.codeforces.com/contest/1558/submission/126903561) failed on test 2 without knowing why. After asserting I found that rope contains unwanted contents and I didn't fix the problem during the contest.↵
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However, when I replace all `__gnu_cxx::rope.erase(x)` into `__gnu_cxx::rope.erase(x, 1)`, my code works fine (idk if it will pass system test or not; at least, it passes asserting that all elements are rolled back to the initial state).↵
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Then! I found it unbelievable to see the following code from [here](http://www.aoc.nrao.edu/php/tjuerges/ALMA/STL/html-4.1.2/rope-source.html#l02310):↵
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Look at the line 2318, comments: `Erase, single character`.↵
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However, it calls `erase(__p, __p + 1);`, who will erase `__p + 1` characters starting from the position `__p`. ↵
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I found it incredible since it's part of libstdc++. I don't know if there's a way to report such failure. Could anyone tell me if I can do something with it? (or instead, NEVER USE SUCH FUNCTION IN THE FUTURE)↵
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Thank you!↵
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**UPD**: I've submitted the [bug](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102048) to gcc.↵
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Fortunately, it's quickly replied by Jonathan Wakely. Unfortunately, just exactly as [user:adamant,2021-08-24] predicted, Jonathan Wakely wrotes:↵
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> We should just delete this class, so I don't have to keep fixing bugs in code that nobody uses or cares about.
↵
However, when I replace all `__gnu_cxx::rope.erase(x)` into `__gnu_cxx::rope.erase(x, 1)`, my code works fine (idk if it will pass system test or not; at least, it passes asserting that all elements are rolled back to the initial state).↵
↵
Then! I found it unbelievable to see the following code from [here](http://www.aoc.nrao.edu/php/tjuerges/ALMA/STL/html-4.1.2/rope-source.html#l02310):↵
↵
↵
↵
↵
Look at the line 2318, comments: `Erase, single character`.↵
↵
However, it calls `erase(__p, __p + 1);`, who will erase `__p + 1` characters starting from the position `__p`. ↵
↵
I found it incredible since it's part of libstdc++. I don't know if there's a way to report such failure. Could anyone tell me if I can do something with it? (or instead, NEVER USE SUCH FUNCTION IN THE FUTURE)↵
↵
Thank you!↵
↵
**UPD**: I've submitted the [bug](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102048) to gcc.↵
↵
Fortunately, it's quickly replied by Jonathan Wakely. Unfortunately, just exactly as [user:adamant,2021-08-24] predicted, Jonathan Wakely wrotes:↵
↵
> We should just delete this class, so I don't have to keep fixing bugs in code that nobody uses or cares about.
