LeetCode 3379: Transformed Array

Meta Data

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Difficulty: easy First Attempt: 2026-02-05

• Submissions: Accepted (first try)

Approach

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Positive moves right and negative moves left by |nums[i]|, which together means landing at i + nums[i]. Wrap with % n for the circular array (Array Template 5); Python’s % gives 0..n-1 even for negatives, so no separate case is needed. nums[i] == 0 lands on itself and yields 0, also covered.

My Solution

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class Solution:
    def constructTransformedArray(self, nums: List[int]) -> List[int]:
        n = len(nums)
        return [nums[(i + x) % n] for i, x in enumerate(nums)]

I originally split positive, negative and zero into three cases; same result.

Complexity

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Time O(n), space O(n) for the output.

Mistakes to Avoid

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• In other languages % can be negative for negative operands; write ((i + x) % n + n) % n.

Interview Explanation

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Moving either way lands at i + nums[i], taken mod n for the circular array; Python’s mod is non-negative even for negatives. Time O(n).