Problem
Create an acronym from the first letter of every word, in uppercase. Spaces and hyphens separate words. Remove every other punctuation mark and digit without adding a separator; an apostrophe inside a word does not start another word. Ignore empty pieces.
Implement acronym_generator(phrase).
Input
phrase: The phrase to shorten.
Output
Return the uppercase initials in their original order.
Constraints
0 ≤ phrase length ≤ 10,000. Input contains ASCII letters, digits, spaces, and punctuation; no tabs or line breaks. A phrase with no letters returns empty text.
Examples
Input:
phrase = "central-processing unit"
Expected output:
expected = "CPU"Input:
std::string phrase = "central-processing unit";
Expected output:
std::string expected = "CPU";Input:
string phrase = "central-processing unit";
Expected output:
string expected = "CPU";Explanation
The hyphen and space separate central, processing, and unit. Their initials are C, P, and U.
Input:
phrase = "don't repeat yourself"
Expected output:
expected = "DRY"Input:
std::string phrase = "don't repeat yourself";
Expected output:
std::string expected = "DRY";Input:
string phrase = "don't repeat yourself";
Expected output:
string expected = "DRY";Explanation
Remove the apostrophe to obtain dont. It is still one word, followed by repeat and yourself.
How to approach it
Try on your own first, then open one hint at a time.
Hint 1
Treat spaces and hyphens as word separators, but ignore digits and other punctuation within or around words.
Hint 2
Look for the first letter after each separator and uppercase it.
Hint 3
Apostrophes inside a word should not create a new word, and empty chunks should be skipped.
Expected complexity
O(n) time, O(n) extra space
References
This challenge is adapted for CodeUtility. Follow the statement and constraints above.