Compilare: user.cpp: In function ‘std::pair<bool, std::vector<std::pair<int, int> > > Solve(int, int)’: user.cpp:47:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0;i < lin.size() && i < col.size();++i){ ^ user.cpp:47:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0;i < lin.size() && i < col.size();++i){ ^ user.cpp:51:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( ; i < lin.size(); ++i){ ^ user.cpp:55:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( ; i < col.size(); ++i){ ^ user.cpp: In function ‘int main()’: user.cpp:69:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("becuri.in","r",stdin); ^ user.cpp:70:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("becuri.out","w",stdout); ^ user.cpp:71:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&n,&m); ^ user.cpp:76:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&x); ^