Compilare: user.cpp: In function ‘int main()’: user.cpp:13:38: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int i = 1;i <= n;++i) s[c[i]].insert(i); ^ user.cpp:25:52: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int k = i;k <= cnt;++k) s[c[k]].erase(s[c[k]].find(k)); ^ user.cpp:25:66: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int k = i;k <= cnt;++k) s[c[k]].erase(s[c[k]].find(k)); ^