Compilare: user.cpp: In function ‘std::vector<int> bellmanFord(int)’: user.cpp:28:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a[k].size(); ++i) ^ user.cpp: In function ‘int bfs(int, int)’: user.cpp:59:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b[k].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:113:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b[d].size(); ++i) ^ user.cpp:146:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a[s].size(); ++i) ^