Each round shows only the question description while the pattern stays hidden. Your goal is to identify the right DSA pattern by reading the wording, constraints, and clue signals.
0/0 correct
0/0 correct
0/0 correct
Difficulty affects both distractor quality and hint subtlety.
Given an array of integers, find the length of the longest palindrome that can be formed using the elements of the array. A palindrome is a sequence that reads the same backward as forward. The function should take an array of integers as input and return the length of the longest palindrome that can be formed. The input array will contain at least one element and at most 3 * 10^4 elements. Each element in the array appears exactly twice except one, which appears only once.
4 clue words prepared
Hidden until you reveal this hint
Hidden until you reveal this hint
Decoding the wording makes it easier to identify the underlying structure of the pattern.
Close distractors help clear confusion, especially in cases like Sliding Window vs Prefix Sum vs Two Pointers.
After reveal, the explanation reinforces your reasoning instead of only giving the answer.
Select one pattern option based on the prompt.
Reveal hints one by one instead of spoiling the answer early.
Submit your guess and inspect the explanation.
Move to the next round without leaving the page.