Level 2 · Question 6

Archived question

Try the question in your own editor, then check your output below.

THE QUESTION

Text from the official booklet. Refer to the PDF for original mathematical notation, formatting, and linked input files. Printed samples and inputs are reproduced as published.

Given a string s, return the longest palindromic substring in s.
Input: A string s
Output: The longest palindromic substring in s
Example:
●    Input: "babad"
●    Output: "bab"
Note: "aba" is also a valid answer.
Input:
“jfjkwegedagedigedagedaogieigosoidirijfgudfidhvsieuggfmfkdhcvosdjewfspisdoesuvbohairkcese
nzezhousuhdbubakdutudvjbdsuehgbdszkutudibygjbdsuegoweoiefegoweoiebiofeabebaooeirhkfo
wiegoodluckyallbfhmfoqielwrboeirhkfowiebfhmfoqielsihghilsjfiworiflskfhggiwueebfndjigpqpaabcd
efghihisjfiejvjfpojojvjfpowfuohwgirlscodedocslrigajojgijriowoifnvkrirlhjshreifpsjdgjdlskfjb”

CHECK YOUR ANSWER

Try your answer.

Run your program in your own editor, then paste its output below. This checks the stated output; it does not assess your full program. Practice attempts do not affect competition scores.

Reveal worked answer

Your output · one valid answer

girlscodedocslrig

Expand around every odd and even centre; keep the longest matching substring. Any equally long palindrome is accepted.

Reveal supplied answer

From the supplied Intermediate answer key. Outputs are reproduced as provided.

Expected output

girlscodedocslrig

Source: GIC 2025 Intermediate Questions and the supplied Intermediate answer key, March 2025 archive.