supertrees.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
supertrees.cpp:39:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
39 | for (int i=1; i<c.size(); i++) {
| ~^~~~~~~~~
supertrees.cpp:46:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
46 | for (int i=0; i<c.size()-1; i++) {
| ~^~~~~~~~~~~
/usr/bin/ld: /tmp/ccux7p9A.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