Compilare: main.cpp: In function 'bool check(long long int)': main.cpp:39:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 39 | for (int i = 0; i < v.size(); i++) | ~~^~~~~~~~~~ main.cpp:32:13: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized] 32 | last--; | ~~~~^~