Compilare: user.cpp: In function ‘void DFS(const std::vector<std::vector<long int> >&, std::stack<long int>&, long int)’: user.cpp:13:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long i = 0; i < adjList[node].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:26:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(input, "%ld %ld", &N, &M); ^ user.cpp:32:35: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(input, "%ld %ld", &u, &v); ^