763. Partition Labels 分区标签

Posted 2020-10-21 Long Long Journey

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.

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。

/**
 * @param {string} S
 * @return {number[]}
 */
var partitionLabels = function (S) {
    let posDict = {};
    for (let i = 0; i < S.length; i++) {
        let char = S[i];
        if (posDict[char]) {
            posDict[char].end = i;
        } else {
            posDict[char] = { start: i, end: i };
        }
    }
    let res = [];
    let min = max = 0;
    for (let i in posDict) {
        let start = posDict[i].start;
        let end = posDict[i].end;
        if (start > max) {
            res.push(max - min + 1);
            [min, max] = [start, end];
        } else {
            max = Math.max(max, end);
        }
    }
    res.push(max - min + 1);
    return res;
};
let S = "ababcbacadefegdehijhklij";
let res = partitionLabels(S);
console.log(res);

来自为知笔记(Wiz)