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Rotate Elements in a List to the Right by K Positions

Certification: Basic Level Accuracy: 55.17% Submissions: 87 Points: 10

Write a Python program that rotates the elements of a list to the right by K positions.

Example 1
    

  • Input: nums = [1, 2, 3, 4, 5], k = 2
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  • Output: [4, 5, 1, 2, 3]
    • 

  • Explanation: 

      

    • Step 1: Original list: [1, 2, 3, 4, 5].
      • 

    • Step 2: Rotate right by 1 position: [5, 1, 2, 3, 4].
      • 

    • Step 3: Rotate right by 1 more position: [4, 5, 1, 2, 3].
      • 

    • Step 4: Total rotations: 2, so the final result is [4, 5, 1, 2, 3].
      • 

    

    •
Example 2
    

  • Input: nums = [7, 8, 9], k = 4
    • 

  • Output: [9, 7, 8]
    • 

  • Explanation: 

      

    • Step 1: Original list: [7, 8, 9].
      • 

    • Step 2: Since k = 4 and the length of the list is 3, we need to rotate by k % len(nums) = 4 % 3 = 1 positions.
      • 

    • Step 3: Rotate right by 1 position: [9, 7, 8].
      • 

    • Step 4: Final result: [9, 7, 8].
      • 

    

    •
Constraints
    

  • 0 ≤ len(list) ≤ 10^5
    • 

  • 0 ≤ k ≤ 10^9
    • 

  • Time Complexity: O(n)
    • 

  • Space Complexity: O(n)
    •
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Hint
Solution

Solution Hints

    
  
  • Use modulo arithmetic to handle large values of k
    • 
  
  • Slice and concatenate: return nums[-k:] + nums[:-k]
    •

Steps to solve by this approach:

 Step 1: Handle edge cases - empty list returns empty list.

 Step 2: Normalize the rotation value k by taking modulo with the list length.

 Step 3: Check if rotation is needed (k = 0 means no rotation).

 Step 4: Split the list into two parts: elements to be rotated and elements to stay.

 Step 5: Concatenate the parts in the new order: rotated elements first, then remaining elements.

 Step 6: Return the rotated list.

Submitted Code :