Compilare: main.cpp:2:0: warning: ignoring #pragma gcc optimize [-Wunknown-pragmas] #pragma gcc optimize("O3") main.cpp: In function 'int main()': main.cpp:35:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int q = 0; q < v[j].size(); ++q) ~~^~~~~~~~~~~~~ main.cpp:49:19: warning: unused variable 'c' [-Wunused-variable] int a, b, c; ^