Compilare: user.cpp: In function ‘void dfG(int)’: user.cpp:14:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[x].size() ; ++i) ^ user.cpp: In function ‘void dfT(int)’: user.cpp:29:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < t[x].size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:71:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0 ; j < ctc[i].size() ; ++j) ^ user.cpp:40:32: 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:41:34: 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:43:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^ user.cpp:44:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &m); ^ user.cpp:48:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &a); ^ user.cpp:49:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &b); ^