highway.cpp: In function 'std::vector<std::pair<long long int, long long int> > bfs(long long int)':
highway.cpp:40:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(long long i = 0; i < adj[u].size(); i++){
~~^~~~~~~~~~~~~~~
/tmp/cczp5hKI.o: In function `main':
grader.cpp:(.text.startup+0x125): undefined reference to `find_pair(int, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, int, int)'
/tmp/cc5V30ZB.o: In function `away(long long, std::vector<long long, std::allocator<long long> > const&, std::vector<long long, std::allocator<long long> > const&)':
highway.cpp:(.text+0x495): undefined reference to `ask(std::vector<long long, std::allocator<long long> > const&)'
/tmp/cc5V30ZB.o: In function `find_pair(long long, std::vector<long long, std::allocator<long long> >, std::vector<long long, std::allocator<long long> >, long long, long long)':
highway.cpp:(.text+0x71e): undefined reference to `ask(std::vector<long long, std::allocator<long long> > const&)'
highway.cpp:(.text+0x7ce): undefined reference to `ask(std::vector<long long, std::allocator<long long> > const&)'
highway.cpp:(.text+0x946): undefined reference to `ask(std::vector<long long, std::allocator<long long> > const&)'
highway.cpp:(.text+0x9a2): undefined reference to `answer(long long, long long)'
collect2: error: ld returned 1 exit status