Check if current sub - string can be arranged into a palindrome
if ( canBePalindrome ( countt ) ) { countt [ str [ end ] ] ++ ; return max ( end - start , maxPal ( str , countt , start , end + 1 ) ) ; } else { countt [ str [ end ] ] ++ ; return maxPal ( str , countt , start , end + 1 ) ; } }