Compilare: user.cpp: In function ‘int main()’: user.cpp:19:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i<A.length();i++) Q[A[i]-'a'].push(i+1); ^ user.cpp:20:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i<B.length();i++){ ^