Compilare: main.cpp: In function 'int main()': main.cpp:37:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for(int j=0;j<vec[i].size();j++) | ~^~~~~~~~~~~~~~ In file included from /usr/include/c++/12.2.1/vector:64, from main.cpp:3: In member function 'constexpr std::vector<_Tp, _Alloc>::size_type std::vector<_Tp, _Alloc>::size() const [with _Tp = int; _Alloc = std::allocator<int>]', inlined from 'int main()' at main.cpp:37:38: /usr/include/c++/12.2.1/bits/stl_vector.h:988:40: warning: iteration 1005 invokes undefined behavior [-Waggressive-loop-optimizations] 988 | { return size_type(this->_M_impl._M_finish - this->_M_impl._M_start); } | ~~~~~~~~~~~~~~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:35:22: note: within this loop 35 | for(int i=0;i<=MOD-1;i++) | ~^~~~~~~