Compilare: user.cpp: In function ‘int main()’: user.cpp:71:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < scc.size(); i++, printf("\n")) ^ user.cpp:72:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < scc[i].size(); j++) ^ user.cpp:53:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in", "r", stdin); ^ user.cpp:54:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out", "w", stdout); ^ user.cpp:57:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:61:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^