Compilare: main.cpp: In function 'std::vector<std::vector<long long int> > prod(std::vector<std::vector<long long int> >, std::vector<std::vector<long long int> >)': main.cpp:24:20: warning: unused variable 'nr1' [-Wunused-variable] 24 | ll nr1=mat1[i][y]; | ^~~ main.cpp:25:20: warning: unused variable 'nr2' [-Wunused-variable] 25 | ll nr2=mat2[y][j]; | ^~~ main.cpp:13:14: warning: variable 'n2' set but not used [-Wunused-but-set-variable] 13 | ll n1,m1,n2,m2; | ^~