1859. Sorting the Sentence

Problem

A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each word consists of lowercase and uppercase English letters.

A sentence can be shuffled by appending the 1-indexed word position to each word then rearranging the words in the sentence.

• For example, the sentence "This is a sentence" can be shuffled as "sentence4 a3 is2 This1" or "is2 sentence4 This1 a3".

Given a shuffled sentence s containing no more than 9 words, reconstruct and return the original sentence.

  Example 1:

Input: s = "is2 sentence4 This1 a3"
Output: "This is a sentence"
Explanation: Sort the words in s to their original positions "This1 is2 a3 sentence4", then remove the numbers.

Example 2:

Input: s = "Myself2 Me1 I4 and3"
Output: "Me Myself and I"
Explanation: Sort the words in s to their original positions "Me1 Myself2 and3 I4", then remove the numbers.

  Constraints:

• 2 <= s.length <= 200

• s consists of lowercase and uppercase English letters, spaces, and digits from 1 to 9.

• The number of words in s is between 1 and 9.

• The words in s are separated by a single space.

• s contains no leading or trailing spaces.

Solution (Java)

class Solution {
    public String sortSentence(String s) {
        String[] words = s.split(" ");
        TreeMap<Integer, String> treeMap = new TreeMap<>();
        for (String word : words) {
            int key = Integer.parseInt(word.charAt(word.length() - 1) + "");
            treeMap.put(key, word.substring(0, word.length() - 1));
        }
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<Integer, String> entry : treeMap.entrySet()) {
            sb.append(entry.getValue());
            sb.append(" ");
        }
        return sb.substring(0, sb.length() - 1);
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).