README_EN.md

comments	difficulty	edit_url	rating	source	tags
true	Easy	https://github.com/doocs/leetcode/edit/main/solution/2100-2199/2129.Capitalize%20the%20Title/README_EN.md	1274	Biweekly Contest 69 Q1	String

2129. Capitalize the Title

中文文档

Description

You are given a string title consisting of one or more words separated by a single space, where each word consists of English letters. Capitalize the string by changing the capitalization of each word such that:

• If the length of the word is 1 or 2 letters, change all letters to lowercase.
• Otherwise, change the first letter to uppercase and the remaining letters to lowercase.

Return the capitalized title.

 

Example 1:

Input: title = "capiTalIze tHe titLe"
Output: "Capitalize The Title"
Explanation:
Since all the words have a length of at least 3, the first letter of each word is uppercase, and the remaining letters are lowercase.

Example 2:

Input: title = "First leTTeR of EACH Word"
Output: "First Letter of Each Word"
Explanation:
The word "of" has length 2, so it is all lowercase.
The remaining words have a length of at least 3, so the first letter of each remaining word is uppercase, and the remaining letters are lowercase.

Example 3:

Input: title = "i lOve leetcode"
Output: "i Love Leetcode"
Explanation:
The word "i" has length 1, so it is lowercase.
The remaining words have a length of at least 3, so the first letter of each remaining word is uppercase, and the remaining letters are lowercase.

 

Constraints:

• 1 <= title.length <= 100
• title consists of words separated by a single space without any leading or trailing spaces.
• Each word consists of uppercase and lowercase English letters and is non-empty.

Solutions

Solution 1: Simulation

Directly simulate the process. Split the string by spaces to get each word, then convert each word to the appropriate case as per the problem statement. Finally, join the words with spaces.

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

Python3

class Solution:
    def capitalizeTitle(self, title: str) -> str:
        words = [w.lower() if len(w) < 3 else w.capitalize() for w in title.split()]
        return " ".join(words)

Java

class Solution {
    public String capitalizeTitle(String title) {
        List<String> ans = new ArrayList<>();
        for (String s : title.split(" ")) {
            if (s.length() < 3) {
                ans.add(s.toLowerCase());
            } else {
                ans.add(s.substring(0, 1).toUpperCase() + s.substring(1).toLowerCase());
            }
        }
        return String.join(" ", ans);
    }
}

C++

class Solution {
public:
    string capitalizeTitle(string title) {
        transform(title.begin(), title.end(), title.begin(), ::tolower);
        istringstream ss(title);
        string ans;
        while (ss >> title) {
            if (title.size() > 2) {
                title[0] = toupper(title[0]);
            }
            ans += title;
            ans += " ";
        }
        ans.pop_back();
        return ans;
    }
};

Go

func capitalizeTitle(title string) string {
	title = strings.ToLower(title)
	words := strings.Split(title, " ")
	for i, s := range words {
		if len(s) > 2 {
			words[i] = strings.Title(s)
		}
	}
	return strings.Join(words, " ")
}

TypeScript

function capitalizeTitle(title: string): string {
    return title
        .split(' ')
        .map(s =>
            s.length < 3 ? s.toLowerCase() : s.slice(0, 1).toUpperCase() + s.slice(1).toLowerCase(),
        )
        .join(' ');
}

C#

public class Solution {
    public string CapitalizeTitle(string title) {
        List<string> ans = new List<string>();
        foreach (string s in title.Split(' ')) {
            if (s.Length < 3) {
                ans.Add(s.ToLower());
            } else {
                ans.Add(char.ToUpper(s[0]) + s.Substring(1).ToLower());
            }
        }
        return string.Join(" ", ans);
    }
}