Compilare: user.cpp: In function ‘std::vector<int, std::allocator<int> > merge(std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)’: user.cpp:122: warning: comparison between signed and unsigned integer expressions user.cpp:122: warning: comparison between signed and unsigned integer expressions user.cpp:135: warning: comparison between signed and unsigned integer expressions user.cpp:140: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:161: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:162: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:163: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:164: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:171: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp:191: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result /tmp/ccRMDcOX.o: In function `main': user.cpp:(.text+0xdcf): warning: the `gets' function is dangerous and should not be used.