highway.cpp: In function 'void dfs(int, int, int, int)':
highway.cpp:14:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<g[u].size();i++){
~^~~~~~~~~~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:37:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int k=0;k<ud[j].size();j++){
~^~~~~~~~~~~~~
highway.cpp:65:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int k=0;k<ud[j].size();j++){
~^~~~~~~~~~~~~
/tmp/cc8K5N7E.o: In function `find_pair(int, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, int, int)':
highway.cpp:(.text+0x277): undefined reference to `ask(std::vector<int, std::allocator<int> >)'
highway.cpp:(.text+0x3c0): undefined reference to `ask(std::vector<int, std::allocator<int> >)'
highway.cpp:(.text+0x519): undefined reference to `ask(std::vector<int, std::allocator<int> >)'
highway.cpp:(.text+0x6c0): undefined reference to `ask(std::vector<int, std::allocator<int> >)'
highway.cpp:(.text+0x819): undefined reference to `ask(std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status