album.cpp: In function `int verif(std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)': album.cpp:25: warning: comparison between signed and unsigned integer expressions album.cpp: In function `int search_for_0(std::vector<int, std::allocator<int> >)': album.cpp:31: warning: comparison between signed and unsigned integer expressions album.cpp:33: warning: control reaches end of non-void function album.cpp: In function `void solve()': album.cpp:43: warning: comparison between signed and unsigned integer expressions album.cpp:47: warning: comparison between signed and unsigned integer expressions album.cpp:37: warning: unused variable `int savepos' album.cpp:37: warning: `int pos1' might be used uninitialized in this function