Compilare: user.cpp: In function ‘int main()’: user.cpp:32:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<G[i].size(); j++){ ^ user.cpp:34:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k=0; k<G[p].size(); k++){ ^ user.cpp:20:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fof.in", "r", stdin); ^ user.cpp:21:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fof.out", "w", stdout); ^ user.cpp:23:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:25:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^