Partition Labels
Created: March 1, 2020 by [lek-tin]
Last updated: March 1, 2020
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
Swill have length in range[1, 500].Swill consist of lowercase letters ('a' to 'z') only.
Solution (Greedy)
class Solution:
def partitionLabels(self, S: str) -> List[int]:
last = {c: i for i, c in enumerate(S)}
j = start = 0
res = []
for i, c in enumerate(S):
j = max(j, last[c])
if i == j:
res.append(i-start+1)
start = i+1
return res