Compilare: user.cpp: In function ‘int main()’: user.cpp:18:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<strlen(s);j++) ^ user.cpp:40:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<a[i][c-'a'].size()&&a[i][c-'a'][j]<=q[i].front();++j); ^ user.cpp:41:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j<a[i][c-'a'].size()&&a[i][c-'a'][j]>q[i].front()) ^