Compilare: user.cpp: In function ‘bool dfs_iterative(int, std::vector<int>&, std::vector<int>&, std::vector<int>&, const std::vector<std::vector<int> >&)’: user.cpp:62:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:83:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < seen.size()) { ^ user.cpp:84:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < seen.size() && seen[i] == 1) ^ user.cpp:86:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i == seen.size()) ^