# 763. Partition Labels 划分字母区间

@TOC

## # 题目描述

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:

1. S will have length in range [1, 500].
2. S will consist of lowercase letters ('a' to 'z') only.

## # 解题方法

``````class Solution(object):
def partitionLabels(self, S):
"""
:type S: str
:rtype: List[int]
"""
lindex = {c: i for i, c in enumerate(S)}
j = anchor = 0
ans = []
for i, c in enumerate(S):
j = max(j, lindex[c])
if i == j:
ans.append(j - anchor + 1)
anchor = j + 1
return ans
``````

C++版本如下：

``````class Solution {
public:
vector<int> partitionLabels(string S) {
map<char, int> d;
for (int i = 0; i < S.size(); i++) d[S[i]] = i;
int start = 0, end = 0;
vector<int> res;
for (int i = 0; i < S.size(); i++) {
end = max(end, d[S[i]]);
if (i == end) {
res.push_back(end - start + 1);
start = end + 1;
}
}
return res;
}
};
``````

## # 日期

2018 年 2 月 5 日 2018 年 12 月 2 日 —— 又到了周日