Compilare: user.cpp: In function ‘void DFS(int, int)’: user.cpp:19:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[Node].size(); ++ i) ^ user.cpp: In function ‘void DFS_Nr(int)’: user.cpp:46:37: 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:89:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < Ans.size(); ++ i) ^ user.cpp:53:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("treespotting.in", "r", stdin); ^ user.cpp:54:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("treespotting.out", "w", stdout); ^ user.cpp:56:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &N, &M); ^ user.cpp:59:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &X, &Y); ^ user.cpp:72:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &X, &Y); ^