Compilare: main.cpp: In function 'int main()': main.cpp:28:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long long i=1;i<=b.size()-n;++i) ~^~~~~~~~~~~~ main.cpp:40:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long long i=0;i<sol.size();++i) ~^~~~~~~~~~~