Compilare: user.cpp: In function ‘void Read()’: user.cpp:27:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < H.size(); ++i) ^ user.cpp: In function ‘void Back(int)’: user.cpp:48:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(w[k] = 0; w[k] < v[k].size(); ++w[k]) ^ user.cpp: In function ‘void Read()’: user.cpp:18:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:22:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&A[i][j]); ^ user.cpp: In function ‘int main()’: user.cpp:99:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("caroiaj.in","r",stdin); ^ user.cpp:100:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("caroiaj.out","w",stdout); ^ user.cpp:103:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^