Compilare: main.cpp: In function 'int main()': main.cpp:15:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < a.size(); ++i){ ~~^~~~~~~~~~ main.cpp:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < b.size(); ++i){ ~~^~~~~~~~~~ main.cpp:34:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (l == a.size()){ ~~^~~~~~~~~~~