Compilare: main.cpp: In function 'int calc2(int)': main.cpp:64:21: warning: array subscript has type 'char' [-Wchar-subscripts] ++F[s[i]]; ^ main.cpp:65:38: warning: array subscript has type 'char' [-Wchar-subscripts] if(ok[s[i]-'a'] && F[s[i]] > 1) ^ main.cpp: In function 'int main()': main.cpp:88:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == 1 || i == s2.size()-1) ~~^~~~~~~~~~~~~~