Clarify the problem requirements first, especially the expected output format and whether the shuffled order is mandatory. Then propose a straightforward O(n) solution that creates a new array of size 2n, fills it with each element and its double, and optionally shuffles the result. Discuss trade-offs and edge cases before coding.
Pro tip: Mention that shuffling can be done in-place using the Fisher-Yates algorithm to avoid extra space, and note that if the problem doesn't require shuffling, you can skip it to save time. This shows you think about efficiency and problem constraints.
Ask about input size, data types, whether the output must be shuffled or if any order is acceptable, and if duplicates in the original array matter.
Explain that you will create a result array of length 2n, iterate through the input, and for each element add it and its double to the result. Then optionally shuffle.
State that the time complexity is O(n) for building the array and O(n) for shuffling, resulting in O(n) overall. Space complexity is O(n) for the output array.
Consider empty array, single element, negative numbers, and large inputs. Mention that shuffling should be unbiased if required.
Write clean code with meaningful variable names, and walk through a small example to verify correctness.
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