[Dinglesberry]

There's literally nothing to do with the code - the key is, how are characters actually represented?

Perhaps your first approach would be.. Are characters maybe actually integers? Does 'a' correspond to a specific int? Could 'b' perhaps be that int + 1, and 'c' that int + 2? Does the integer value of characters sequentially increase (here's a tip, it does).

The only different is, rather than a int[] array, the function would take a char[] array. Good luck.