Problem

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.

Examples

Example 1:

1
2
3
4

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:

1
2
3
4
5

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:

1
2
3
4
5

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.

Solution

Method 1 - Split the string

We need to capitalize each word in the given string title based on its length. If the word is 1 or 2 characters long, we’ll convert the entire word to lowercase. Otherwise, we’ll capitalize the first character and convert the rest to lowercase.

Here is the approach:

  1. Split the string title into words using the space delimiter.
  2. For each word, check its length:
    • If the length is 1 or 2, convert the word to lowercase.
    • If the length is greater than 2, convert the first character to uppercase and the rest to lowercase.
  3. Join the processed words back into a single string with spaces in between.
  4. Return the resulting string.

Code

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19

class Solution {
    public String capitalizeTitle(String title) {
        String[] words = title.split(" ");
        StringBuilder ans = new StringBuilder();

        for (String word : words) {
            if (word.length() <= 2) {
                ans.append(word.toLowerCase());
            } else {
                ans.append(Character.toUpperCase(word.charAt(0)))
                .append(word.substring(1).toLowerCase());
            }
            ans.append(" ");
        }

        // Remove the trailing space
        return ans.toString().trim();
    }
}
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12

class Solution:
    def capitalizeTitle(self, title: str) -> str:
        words: List[str] = title.split()
        ans: List[str] = []
        
        for word in words:
            if len(word) <= 2:
                ans.append(word.lower())
            else:
                ans.append(word[0].upper() + word[1:].lower())
        
        return " ".join(ans)

Complexity

  • ⏰ Time complexity: O(n), where n is the length of the string title. This is because we have to traverse through each character in the string to process it.
  • 🧺 Space complexity: O(n). This is because we are storing the processed words in a list and the final joined string.