Compilare: user.cpp: In function ‘void Add(int, int, int)’: user.cpp:30:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(D[j][size[j]-1].size()==Lg+1) ^ user.cpp: In function ‘int main()’: user.cpp:38:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grid.in","r",stdin); ^ user.cpp:39:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grid.out","w",stdout); ^