Compilare: user.cpp: In function ‘void DFS(long int, bool*, std::vector<long int>*, std::stack<long int>)’: user.cpp:15:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i{0};i < G[node].size();++i){ ^ user.cpp: In function ‘int main()’: user.cpp:24:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in", "r", stdin); ^ user.cpp:25:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out", "w",stdout); ^ user.cpp:33:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld ", &N, &M); ^ user.cpp:35:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld ", &x, &y); ^