Compilare: user.cpp: In function 'int get_edge(int, int)': user.cpp:11: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void add(std::vector<int, std::allocator<int> >, int)': user.cpp:20: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'std::pair<int, int> find(std::vector<int, std::allocator<int> >)': user.cpp:37: warning: comparison between signed and unsigned integer expressions user.cpp:39: warning: comparison between signed and unsigned integer expressions user.cpp:47: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int main()': user.cpp:36: warning: 'next' may be used uninitialized in this function user.cpp:36: note: 'next' was declared here