A string S of lowercase letters is given. We want to partition this string into
as many parts as possible so that each letter appears in at most one part, and return a list
of integers representing the size of these parts.
Example 1:
Input: S = "ababcbacadefegdehijhklij" Output: [9,7,8] Explanation: The partition is "ababcbaca", "defegde", "hijhklij". This is a partition so that each letter appears in at most one part. A partition like "ababcbacadefegde", "hijhklij" is incorrect, because it splits S into less parts.
Note:
S will have length in range [1, 500].S will consist of lowercase letters ('a' to 'z')
only.