Compilare: user.cpp: In function ‘void bck()’: user.cpp:25:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < rem.size(); i++) ^ user.cpp:29:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[x].size(); j++) ^ user.cpp:36:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[x].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:44:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("teroristi2.in", "r", stdin); ^ user.cpp:45:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("teroristi2.out", "w", stdout); ^ user.cpp:48:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &mod); ^ user.cpp:51:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^