Problem	4sum
User	R9q5P8
Submission Time	2026-04-20 12:39:18
Score	0
Max Time	N/A
Max Memory	N/A

Compile Error

4sum.cpp: In function ‘int main()’:
4sum.cpp:15:16: error: ‘begin’ was not declared in this scope
15 | for (auto tb:b)
| ^
4sum.cpp:15:16: note: suggested alternatives:
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:95,
from 4sum.cpp:1:
/usr/include/c++/9/valarray:1224:5: note: ‘std::begin’
1224 | begin(const valarray<_Tp>& __va)
| ^~~~~
In file included from /usr/include/c++/9/filesystem:38,
from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:129,
from 4sum.cpp:1:
/usr/include/c++/9/bits/fs_dir.h:516:3: note: ‘std::filesystem::__cxx11::begin’
516 | begin(recursive_directory_iterator __iter) noexcept
| ^~~~~
4sum.cpp:15:16: error: ‘end’ was not declared in this scope
15 | for (auto tb:b)
| ^
4sum.cpp:15:16: note: suggested alternatives:
In file included from /us