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1859. Sorting the Sentence

Description

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.

Solutions

Solution 1: String Splitting

First, we split the string $s$ by spaces to get the string array $words$. Then, we create a string array $ans$ of length $ words $ to store the answer.
Next, we iterate over each string $w$ in the string array $words$, find the position $i$ represented by the last character of $w$, then take the first $ w -1$ characters of $w$ as the new string $w’$, and place $w’$ in the $i$th position of the array $ans$.

Finally, we join the array $ans$ into a string by spaces, which is the answer.

The time complexity is $O(n)$, and the space complexity is $O(n)$. Where $n$ is the length of the string $s$.

  • class Solution {
        public String sortSentence(String s) {
            String[] ws = s.split(" ");
            int n = ws.length;
            String[] ans = new String[n];
            for (int i = 0; i < n; ++i) {
                String w = ws[i];
                ans[w.charAt(w.length() - 1) - '1'] = w.substring(0, w.length() - 1);
            }
            return String.join(" ", ans);
        }
    }
    
  • class Solution {
    public:
        string sortSentence(string s) {
            istringstream iss(s);
            string w;
            vector<string> ws;
            while (iss >> w) {
                ws.push_back(w);
            }
            vector<string> ss(ws.size());
            for (auto& w : ws) {
                ss[w.back() - '1'] = w.substr(0, w.size() - 1);
            }
            string ans;
            for (auto& w : ss) {
                ans += w + " ";
            }
            ans.pop_back();
            return ans;
        }
    };
    
  • class Solution:
        def sortSentence(self, s: str) -> str:
            ws = [(w[:-1], int(w[-1])) for w in s.split()]
            ws.sort(key=lambda x: x[1])
            return ' '.join(w for w, _ in ws)
    
    
  • func sortSentence(s string) string {
    	ws := strings.Split(s, " ")
    	ans := make([]string, len(ws))
    	for _, w := range ws {
    		ans[w[len(w)-1]-'1'] = w[:len(w)-1]
    	}
    	return strings.Join(ans, " ")
    }
    
  • function sortSentence(s: string): string {
        const ws = s.split(' ');
        const ans = Array(ws.length);
        for (const w of ws) {
            ans[w.charCodeAt(w.length - 1) - '1'.charCodeAt(0)] = w.slice(0, -1);
        }
        return ans.join(' ');
    }
    
    
  • /**
     * @param {string} s
     * @return {string}
     */
    var sortSentence = function (s) {
        const ws = s.split(' ');
        const ans = Array(ws.length);
        for (const w of ws) {
            ans[w.charCodeAt(w.length - 1) - '1'.charCodeAt(0)] = w.slice(0, -1);
        }
        return ans.join(' ');
    };
    
    

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