Compilare: user.cpp: In function ‘std::vector<int> aduna(std::vector<int>, std::vector<int>)’: user.cpp:36:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( j >= a.size() ) ^ user.cpp:38:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = j; i < b.size(); i++) ^ user.cpp:49:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( j >= b.size() ) ^ user.cpp:51:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = j; i < a.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:77:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("aladdin2.in","r",stdin); ^ user.cpp:78:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("aladdin2.out","w",stdout); ^ user.cpp:80:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &M, &N); ^ user.cpp: In function ‘std::vector<int> aduna(std::vector<int>, std::vector<int>)’: user.cpp:19:9: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] int j; ^