Compilare: main.cpp: In function 'void solve(long long unsigned int)': main.cpp:57:27: warning: array subscript has type 'char' [-Wchar-subscripts] g<<sol<<' '<<nr*a[s[r]]; ^ main.cpp: In function 'int main()': main.cpp:63:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] f>>s+1; ~^~ main.cpp:65:15: warning: array subscript has type 'char' [-Wchar-subscripts] a[s[i]]++; ^