Given a complete binary tree, reverse the nodes present at alternate levels.
Example 1:
Input:
1
/ \
3 2
Output:
1
/ \
2 3
Explanation: Nodes at level 2 are reversed.
Example 2:
Input:
1
/ \
2 3
/ \ / \
42 51 63 72
Output:
1
/ \
3 2
/ \ / \
42 51 63 72
Explanation:
Nodes at level 2 are reversed.
Level 1 and 3 remain as it is.
Your Task:
You dont need to read input or print anything. Complete the function reverseAlternate() which takes root node as input parameter and modifies the given tree in-place.
Note: If you click on Compile and Test the output will be the in-order traversal of the modified tree.
Expected Time Complexity: O(N)
Expected Auxiliary Space: O(height of tree)

Constraints:
1 ≤ N ≤ 10^4

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