3819. Rotate Non Negative Elements

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You are given an integer array nums and an integer k.

Rotate only the non-negative elements of the array to the left by k positions, in a cyclic manner.

All negative elements must stay in their original positions and must not move.

After rotation, place the non-negative elements back into the array in the new order, filling only the positions that originally contained non-negative values and skipping all negative positions.

Return the resulting array.

 

Example 1:

Input: nums = [1,-2,3,-4], k = 3

Output: [3,-2,1,-4]

Explanation:​​​​​​​

  • The non-negative elements, in order, are [1, 3].
  • Left rotation with k = 3 results in:
    • [1, 3] -> [3, 1] -> [1, 3] -> [3, 1]
  • Placing them back into the non-negative indices results in [3, -2, 1, -4].

Example 2:

Input: nums = [-3,-2,7], k = 1

Output: [-3,-2,7]

Explanation:

  • The non-negative elements, in order, are [7].
  • Left rotation with k = 1 results in [7].
  • Placing them back into the non-negative indices results in [-3, -2, 7].

Example 3:

Input: nums = [5,4,-9,6], k = 2

Output: [6,5,-9,4]

Explanation:

  • The non-negative elements, in order, are [5, 4, 6].
  • Left rotation with k = 2 results in [6, 5, 4].
  • Placing them back into the non-negative indices results in [6, 5, -9, 4].

 

Constraints:

  • 1 <= nums.length <= 105
  • -105 <= nums[i] <= 105
  • 0 <= k <= 105

Hints

Hint 1
Pull out non-negative values and their indices.
Hint 2
Left-rotate the values by k (use k %= m where m is their count).
Hint 3
Put the rotated values back into the stored indices; leave negatives as-is and return the array.