Table: user_content
+-------------+---------+ | Column Name | Type | +-------------+---------+ | content_id | int | | content_text| varchar | +-------------+---------+ content_id is the unique key for this table. Each row contains a unique ID and the corresponding text content.
Write a solution to transform the text in the content_text column by applying the following rules:
-, both parts should be capitalized (e.g., top-rated → Top-Rated)Return the result table that includes both the original content_text and the modified text following the above rules.
The result format is in the following example.
Example:
Input:
user_content table:
+------------+---------------------------------+ | content_id | content_text | +------------+---------------------------------+ | 1 | hello world of SQL | | 2 | the QUICK-brown fox | | 3 | modern-day DATA science | | 4 | web-based FRONT-end development | +------------+---------------------------------+
Output:
+------------+---------------------------------+---------------------------------+ | content_id | original_text | converted_text | +------------+---------------------------------+---------------------------------+ | 1 | hello world of SQL | Hello World Of Sql | | 2 | the QUICK-brown fox | The Quick-Brown Fox | | 3 | modern-day DATA science | Modern-Day Data Science | | 4 | web-based FRONT-end development | Web-Based Front-End Development | +------------+---------------------------------+---------------------------------+
Explanation:
The First Letter Capitalization II problem focuses on correctly transforming text so that words follow specific capitalization rules. Instead of simply capitalizing the first character, the challenge usually involves carefully scanning the string, identifying valid word boundaries, and ensuring only the correct letters are modified while preserving the rest of the characters.
A common strategy is to iterate through the string character by character while tracking whether the current character begins a new word. When a word start is detected, convert the letter to uppercase; otherwise keep the remaining characters unchanged or normalized based on the rule set. Edge cases such as multiple spaces, punctuation, or already-capitalized letters must be handled carefully.
Using a StringBuilder (or equivalent mutable structure) helps build the final string efficiently while scanning the input once. This approach ensures predictable performance and avoids repeated string copying. The key idea is recognizing word boundaries and applying capitalization rules only when necessary.
The optimized solution typically runs in O(n) time where n is the string length, with minimal additional memory.
| Approach | Time Complexity | Space Complexity |
|---|---|---|
| Single Pass String Traversal | O(n) | O(n) |
| In-place Character Processing (language dependent) | O(n) | O(1) to O(n) |
Greg Hogg
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Yes, string manipulation and formatting problems are common in coding interviews. Variations of capitalization or word-processing challenges are often used to test attention to detail and efficient iteration over strings.
A mutable string structure such as StringBuilder (Java), StringBuilder/StringBuffer equivalents, or a character array works best. These allow efficient character updates while building the result without repeated string copying.
The optimal approach is to scan the string once while tracking whether the current position marks the start of a new word. When a new word begins, convert that character to uppercase and append the rest normally. This ensures the transformation is done efficiently in linear time.
Important edge cases include multiple spaces, punctuation marks, empty strings, and words that are already capitalized. Handling boundaries correctly ensures only the intended characters are transformed.