1. How do you perform tree traversal iteratively?

2. Convert Binary Tree to Mirror Tree Convert a given binary tree into its mirror tree, where the left and right children of all non-leaf nodes are interchanged. Input: An integer ‘T’ denoting the number of test cases. For each test case, the elements of the tree in level order form, separated by a single space. Use -1 in place of a null left or right child. Output: For each test case, the inorder traversal of the mirror tree, printed on a separate line. Example: Input: 11 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1 Output: 7 4 2 1 6 3 5 Constraints: 1 <= T <= 100 1 <= N <= 3000 -10^9 <= DATA <= 10^9 Note: Modify the binary tree in place to get the mirror, without creating a new tree.

3. Write a multithreaded program to scan three large log files for different patterns and write the matches to an output file, ensuring minimal memory usage.

4. Given an array of integers that is initially increasing and then decreasing, find a target value using a binary search approach.

5. Given an integer, count the number of digits in it.