Compilare: user.cpp: In function ‘std::vector<int> gensubsir(std::vector<bool>, int)’: user.cpp:13:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int i = 0; i < bitmask.size(); ++ i) ^ user.cpp: In function ‘bool next(std::vector<bool>&)’: user.cpp:26:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while( i < bitmask.size() and bitmask[i] ) { ^ user.cpp:31:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < bitmask.size()) { ^ user.cpp: In function ‘bool compact(std::vector<int>)’: user.cpp:52:12: warning: statement has no effect [-Wunused-value] for( st; st <= MAX_N; ++ st) { ^ user.cpp:54:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(count == pf.size()) ^ user.cpp: In function ‘int main()’: user.cpp:103:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(supercompact(vt) and vt.size() > maxim) ^ user.cpp: In function ‘bool compact(std::vector<int>)’: user.cpp:59:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:91:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("compact2.in", "r", stdin); ^ user.cpp:92:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("compact2.out", "w", stdout); ^ user.cpp:94:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:96:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^