Compilare: main.cpp: In function 'int main()': main.cpp:13:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] cin>>s+1; ~^~ main.cpp:17:15: warning: array subscript has type 'char' [-Wchar-subscripts] f[s[i]] += n-i+1; ^ main.cpp:26:39: warning: array subscript has type 'char' [-Wchar-subscripts] sol = (sol + i * (sum - f[s[i]]) % MOD) % MOD; ^ main.cpp:28:15: warning: array subscript has type 'char' [-Wchar-subscripts] f[s[i]] -= n-i+1; ^