it denotes both pointer at same position and we don 't  have sufficient char to make  palindrome string
if ( left == right ) { return - 1 ; } else { for ( int j = right ; j < n - left - 1 ; j ++ ) { char t = s [ j ] ; s [ j ] = s [ j + 1 ] ; s [ j + 1 ] = t ; count ++ ; } } } return count ; }