Compilare: main.cpp: In function 'int main()': main.cpp:36:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | 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 void std::vector<_Tp, _Alloc>::clear() [with _Tp = int; _Alloc = std::allocator<int>]', inlined from 'int main()' at main.cpp:45:25: /usr/include/c++/12.2.1/bits/stl_vector.h:1601:24: warning: iteration 1004 invokes undefined behavior [-Waggressive-loop-optimizations] 1601 | { _M_erase_at_end(this->_M_impl._M_start); } | ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:43:22: note: within this loop 43 | for(int i=1;i<=100005;i++) | ~^~~~~~~~