Compilare: main.cpp: In function 'int main()': main.cpp:30:15: warning: array subscript has type 'char' [-Wchar-subscripts] 30 | f1[a[i]]--; | ~~~^ main.cpp:31:18: warning: array subscript has type 'char' [-Wchar-subscripts] 31 | if(f2[a[i]]){ | ~~~^ main.cpp:32:62: warning: array subscript has type 'char' [-Wchar-subscripts] 32 | while(!st.empty() && a[i] < st.top() && f1[st.top()] > f2[st.top()]){ | ~~~~~~^~ main.cpp:32:77: warning: array subscript has type 'char' [-Wchar-subscripts] 32 | while(!st.empty() && a[i] < st.top() && f1[st.top()] > f2[st.top()]){ | ~~~~~~^~ main.cpp:33:26: warning: array subscript has type 'char' [-Wchar-subscripts] 33 | f2[st.top()]++; | ~~~~~~^~ main.cpp:37:19: warning: array subscript has type 'char' [-Wchar-subscripts] 37 | f2[a[i]]--; | ~~~^