Compilare: user.cpp: In function ‘int main()’: user.cpp:39:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (a[a[i][l-1]].size()>=l) a[i].push_back(a[a[i][l-1]][l-1]); ^ user.cpp:58:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (a[q].size()>=l) q=a[q][l]; ^