Compilare: user.cpp: In function ‘int main()’: user.cpp:20:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<s.size()-1) ~^~~~~~~~~~~ user.cpp:21:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] nxt[i][s[i+1]]=i+1; ^ user.cpp:27:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(i=nxt[0][a[0]];i<=l&&i!=0;i=nxt[i][a[0]]) ^ user.cpp:27:52: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(i=nxt[0][a[0]];i<=l&&i!=0;i=nxt[i][a[0]]) ^ user.cpp:29:55: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(p=i,ch=1;p!=0&&ch<len;p=nxt[p][a[ch++]]); ^