Compilare: main.cpp: In function 'void c1()': main.cpp:25:23: warning: unused variable 'b' [-Wunused-variable] 25 | int sum = 0 , b = __builtin_popcount(i) , fb; | ^ main.cpp: In lambda function: main.cpp:60:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 60 | for(int k = 1 ; k <= SZ(v[x]) ; ++ k){ | ^ main.cpp: In function 'void c1()': main.cpp:25:51: warning: 'fb' may be used uninitialized in this function [-Wmaybe-uninitialized] 25 | int sum = 0 , b = __builtin_popcount(i) , fb; | ^~