A string S of lowercase English 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]
class Solution { public List<Integer> partitionLabels(String S) { if(S == null || S.length() == 0){ return null; } List<Integer> list = new ArrayList<>(); int[] map = new int[26]; // record the last index of the each char for(int i = 0; i < S.length(); i++){ map[S.charAt(i)-'a'] = i; } // record the end index of the current sub string int last = 0; int start = 0; for(int i = 0; i < S.length(); i++){ last = Math.max(last, map[S.charAt(i)-'a']); if(last == i){ list.add(last - start + 1); start = last + 1; } } return list; } }