1592. Rearrange Spaces Between Words

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Description

You are given a string text of words that are placed among some number of spaces. Each word consists of one or more lowercase English letters and are separated by at least one space. It's guaranteed that text contains at least one word.

Rearrange the spaces so that there is an equal number of spaces between every pair of adjacent words and that number is maximized. If you cannot redistribute all the spaces equally, place the extra spaces at the end, meaning the returned string should be the same length as text.

Return the string after rearranging the spaces.

 

Example 1:

Input: text = "  this   is  a sentence "
Output: "this   is   a   sentence"
Explanation: There are a total of 9 spaces and 4 words. We can evenly divide the 9 spaces between the words: 9 / (4-1) = 3 spaces.

Example 2:

Input: text = " practice   makes   perfect"
Output: "practice   makes   perfect "
Explanation: There are a total of 7 spaces and 3 words. 7 / (3-1) = 3 spaces plus 1 extra space. We place this extra space at the end of the string.

 

Constraints:

• 1 <= text.length <= 100
• text consists of lowercase English letters and ' '.
• text contains at least one word.

Solutions

Solution 1: String Simulation

First, we count the number of spaces in the string $\textit{text}$, denoted as $\textit{spaces}$. Then, we split $\textit{text}$ by spaces into an array of strings $\textit{words}$. Next, we calculate the number of spaces that need to be inserted between adjacent words and perform the concatenation. Finally, we append the remaining spaces to the end.

The time complexity is $O(n)$, and the space complexity is $O(n)$, where $n$ represents the length of the string $\textit{text}$.

Python3

class Solution:
    def reorderSpaces(self, text: str) -> str:
        spaces = text.count(" ")
        words = text.split()
        if len(words) == 1:
            return words[0] + " " * spaces
        cnt, mod = divmod(spaces, len(words) - 1)
        return (" " * cnt).join(words) + " " * mod

Java

class Solution {
    public String reorderSpaces(String text) {
        int spaces = 0;
        for (char c : text.toCharArray()) {
            if (c == ' ') {
                ++spaces;
            }
        }
        String[] words = text.trim().split("\\s+");
        if (words.length == 1) {
            return words[0] + " ".repeat(spaces);
        }
        int cnt = spaces / (words.length - 1);
        int mod = spaces % (words.length - 1);
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < words.length; ++i) {
            sb.append(words[i]);
            if (i < words.length - 1) {
                sb.append(" ".repeat(cnt));
            }
        }
        sb.append(" ".repeat(mod));
        return sb.toString();
    }
}

C++

class Solution {
public:
    string reorderSpaces(string text) {
        int spaces = ranges::count(text, ' ');
        auto words = split(text);

        if (words.size() == 1) {
            return words[0] + string(spaces, ' ');
        }

        int cnt = spaces / (words.size() - 1);
        int mod = spaces % (words.size() - 1);

        string result = join(words, string(cnt, ' '));
        result += string(mod, ' ');

        return result;
    }

private:
    vector<string> split(const string& text) {
        vector<string> words;
        istringstream stream(text);
        string word;
        while (stream >> word) {
            words.push_back(word);
        }
        return words;
    }

    string join(const vector<string>& words, const string& separator) {
        ostringstream result;
        for (size_t i = 0; i < words.size(); ++i) {
            result << words[i];
            if (i < words.size() - 1) {
                result << separator;
            }
        }
        return result.str();
    }
};

Go

func reorderSpaces(text string) string {
	cnt := strings.Count(text, " ")
	words := strings.Fields(text)
	m := len(words) - 1
	if m == 0 {
		return words[0] + strings.Repeat(" ", cnt)
	}
	return strings.Join(words, strings.Repeat(" ", cnt/m)) + strings.Repeat(" ", cnt%m)
}

TypeScript

function reorderSpaces(text: string): string {
    const spaces = (text.match(/ /g) || []).length;
    const words = text.split(/\s+/).filter(Boolean);
    if (words.length === 1) {
        return words[0] + ' '.repeat(spaces);
    }
    const cnt = Math.floor(spaces / (words.length - 1));
    const mod = spaces % (words.length - 1);
    const result = words.join(' '.repeat(cnt));
    return result + ' '.repeat(mod);
}

Rust

impl Solution {
    pub fn reorder_spaces(text: String) -> String {
        let spaces = text.chars().filter(|&c| c == ' ').count();
        let words: Vec<&str> = text.split_whitespace().collect();
        if words.len() == 1 {
            return format!("{}{}", words[0], " ".repeat(spaces));
        }
        let cnt = spaces / (words.len() - 1);
        let mod_spaces = spaces % (words.len() - 1);
        let result = words.join(&" ".repeat(cnt));
        result + &" ".repeat(mod_spaces)
    }
}