/tmp/ccO6oLOI.o: In function `count_common_roads(std::vector<int, std::allocator<int> > const&)':
grader.cpp:(.text+0x280): multiple definition of `count_common_roads(std::vector<int, std::allocator<int> > const&)'
/tmp/ccyQK94I.o:simurgh.cpp:(.text+0xf0): first defined here
/tmp/ccO6oLOI.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccyQK94I.o:simurgh.cpp:(.text.startup+0x0): first defined here
/tmp/ccyQK94I.o: In function `main':
simurgh.cpp:(.text.startup+0x165): undefined reference to `find_roads(int, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)'
/tmp/ccO6oLOI.o: In function `main':
grader.cpp:(.text.startup+0x2d9): undefined reference to `find_roads(int, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status