LeetCode 763. Partition Labels

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.

题目大意:给出一个小写字母的字符串S. 我们想把这个字符串分成尽可能多的部分,这样每个字母最多只出现一个部分,并返回一个表示这些部分大小的整数列表。

分析:遍历字符串,找到S[i]在S中最后一次出现的位置标记为end,end位置是当前要切割的字串部分最短的结尾处,当i == end时候说明start~end可以组成一个最短部分串,将这个部分串的长度(end – start + 1)放入ans数组中,然后将start标记为下一个部分串的开始(end+1),最后返回ans数组~