Compilare: user.cpp: In function ‘int main()’: user.cpp:39:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (a[i].size() > m1) { m2 = m1; m1 = a[i].size(); p2 = p1; p1 = i;} ^ user.cpp:40:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if (a[i].size() > m2) { m2 = a[i].size(); p2 = i;} ^ user.cpp:50:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol.size(); i++) ^