Given an array, reverse every sub-array formed by consecutive k elements.
Input: arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], k = 3.
Output: [3, 2, 1, 6, 5, 4, 9, 8, 7, 10]
Input: arr = [1, 2, 3, 4, 5, 6, 7], k = 5.
Output: [5, 4, 3, 2, 1, 7, 6]
- We will use two pointers technique to solve this problem.
- First, we will initialize our 1st pointer d with value k-1 (d = k-1) and a variable m with value 2 (m = 2).
Now, we will iterate the array with our 2nd pointer i and check
- If i < d, Swap (arr[i], arr[d]) and decrement d by 1. Otherwise,
- Make d = k * m – 1, i = k * (m – 1) – 1 and m = m + 1.
Below is the implementation of the above approach.
3 2 1 6 5 4 7
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