Compilare: main.cpp: In function 'int main()': main.cpp:48:17: warning: array subscript has type 'char' [-Wchar-subscripts] f1[s1[i]]++; ^ main.cpp:53:17: warning: array subscript has type 'char' [-Wchar-subscripts] f2[s2[i]]++; ^ main.cpp:60:46: warning: array subscript has type 'char' [-Wchar-subscripts] while ( st.size() > 0 && f2[s1[i]] && f2[st.top()] + 1 <= f1[st.top()] && s1[i] < st.top()) ^ main.cpp:62:26: warning: array subscript has type 'char' [-Wchar-subscripts] if ( f2[s1[i]] > 0 ) { ^ main.cpp:63:25: warning: array subscript has type 'char' [-Wchar-subscripts] f2[s1[i]]--; ^ main.cpp:67:21: warning: array subscript has type 'char' [-Wchar-subscripts] f1[s1[i]]--; ^