Compilare: user.cpp: In function ‘int main()’: user.cpp:30:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < out[i].size(); ++j) { ^ user.cpp:21:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("proc2.in","r",stdin); ^ user.cpp:22:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("proc2.out","w",stdout); ^ user.cpp:24:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:29:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^