LeetCode 763 Partition Labels - Problem Statement

Partition a string into as many parts as possible so that each letter appears in at most one part.

With s = "ababcbacadefegdehijhklij":

• "ababcbaca" contains all 'a', 'b', 'c'. Length 9.
• "defegde" contains all 'd', 'e'. Length 7.
• "hijhklij" contains all 'h', 'i', 'j', 'k', 'l'. Length 8.
• Result: [9, 7, 8].

With s = "eccbbbbdec":

• "eccbbbbdec" must be one part (letters overlap throughout).
• Result: [10].

Return the list of partition sizes.

Constraints: $1 \le$ s.length $\le 500$. All lowercase letters.