supertrees.cpp: In function 'int main()':
supertrees.cpp:32:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
32 | freopen("02.in", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
/usr/bin/ld: /tmp/cchqgqQr.o: in function `build(std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > >)':
grader.cpp:(.text+0x260): multiple definition of `build(std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > >)'; /tmp/ccsUZcKq.o:supertrees.cpp:(.text+0x180): first defined here
/usr/bin/ld: /tmp/cchqgqQr.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccsUZcKq.o:supertrees.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/ccsUZcKq.o: in function `main':
supertrees.cpp:(.text.startup+0x2bc): undefined reference to `construct(std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > >)'
/usr/bin/ld: /tmp/cchqgqQr.o: in function `main':
grader.cpp:(.text.startup+0x39a): undefined reference to `construct(std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > >)'
collect2: error: ld returned 1 exit status