Alpha and Arabic
Given a set of character, Ex: 'A', 'B', 'C'
each char have its representative number:
A = 1, B = 13, C = 110
When the character next to the current index is smaller than the current we add
Ex: CBA= 110+ 13+ 1
When the character next to the current index is bigger than current we all the answer in previous will become minus sign(but not the last one) ABC = -1 -13+110 = 96