My submission on the problem Parse Tree(C++14) failed to compile, and the error message is:

Can't compile file:

C:/Programs/mingw-w64/bin/../lib/gcc/i686-w64-mingw32/6.2.0/../../../../i686-w64-mingw32/lib/../lib/crt2.o:crtexe.c:(.text+0x8c): undefined reference to _MINGW_INSTALL_DEBUG_MATHERR

C:/Programs/mingw-w64/bin/../lib/gcc/i686-w64-mingw32/6.2.0\libstdc++.a(c++locale.o):(.text$_ZSt14__convert_to_vIfEvPKcRT_RSt12_Ios_IostateRKPi+0x6a): undefined reference to __mingw_strtof

C:/Programs/mingw-w64/bin/../lib/gcc/i686-w64-mingw32/6.2.0\libstdc++.a(c++locale.o):(.text$_ZSt14__convert_to_vIdEvPKcRT_RSt12_Ios_IostateRKPi+0x6a): undefined reference to __mingw_strtod

collect2.exe: error: ld returned 1 exit status

But when I was using C++11, there was no problem. My code is here:

https://gist.github.com/ascchrvalstr/d2c60d0cf2567a929b8a4499cef00b49

I already solved over 130 problems,but when I open the problemset standings,I saw the number 126.And,sometimes,when I open it again,I see the correct number.I think this may be a bug.

At my opinion,tags are good for beginners.However,after someone learns programming for a period of time,he/she will find that tags are not good for him/her any more because they make problems pointless.And if someone doesn't login to Codeforces,the tags will automaticly show in the problem description.

I used to be a lover of this language.And this language is in the top 10 list in programming languages(according to the list now).If Codeforces really adds this language,I will feel happy.

The verification image uses Google Api.But Google is blocked in China.