Compilare: main.cpp: In function 'int main()': main.cpp:50:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a[uc].y.size();i++) ~^~~~~~~~~~~~~~~ main.cpp:51:30: warning: array subscript has type 'char' [-Wchar-subscripts] fr[a[uc].y[i]]++; ^ main.cpp:57:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;i<a[i].y.size();j++) ~^~~~~~~~~~~~~~ main.cpp:59:40: warning: array subscript has type 'char' [-Wchar-subscripts] if(fr[a[i].y[j]]==0) ok=0; ^