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Rotate Array by K Steps

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 5

Write a JavaScript program to rotate an array to the right by k steps. Each element should move k positions to the right, with elements at the end wrapping around to the beginning.

Example 1
    
  
  • Input: nums = [1, 2, 3, 4, 5, 6, 7], k = 3
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  • Output: [5, 6, 7, 1, 2, 3, 4]
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  • Explanation: 
    • Original array is [1, 2, 3, 4, 5, 6, 7] and k = 3. 
    • After 1 rotation: [7, 1, 2, 3, 4, 5, 6]. 
    • After 2 rotations: [6, 7, 1, 2, 3, 4, 5]. 
    • After 3 rotations: [5, 6, 7, 1, 2, 3, 4].
    •
Example 2
    
  
  • Input: nums = [-1, -100, 3, 99], k = 2
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  • Output: [3, 99, -1, -100]
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  • Explanation: 
    • Original array is [-1, -100, 3, 99] and k = 2. 
    • After 1 rotation: [99, -1, -100, 3]. 
    • After 2 rotations: [3, 99, -1, -100].
    •
Constraints
    
  
  • 1 ≤ nums.length ≤ 10^5
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  • -2^31 ≤ nums[i] ≤ 2^31 - 1
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  • 0 ≤ k ≤ 10^5
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  • Time Complexity: O(n)
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  • Space Complexity: O(1) for in-place solution
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Hint
Solution

Solution Hints

    
  
  • Use the reverse technique to rotate the array efficiently
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  • First, reverse the entire array
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  • Then reverse the first k elements
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  • Finally, reverse the remaining elements from k to end
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  • Handle the case where k is greater than array length using modulo operation
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  • This approach works in-place without using extra space
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Steps to solve by this approach:

 Step 1: Calculate k modulo array length to handle cases where k is greater than array size.
 Step 2: Reverse the entire array from index 0 to n-1.
 Step 3: Reverse the first k elements from index 0 to k-1.
 Step 4: Reverse the remaining elements from index k to n-1.
 Step 5: The array is now rotated by k positions to the right.
 Step 6: Use a helper reverse function that swaps elements using two pointers approach.
 Step 7: This approach modifies the array in-place without using extra space.

Submitted Code :