P10765 「CROI · R2」Under the Peach Tree of Longing I

> Year after year under the peach tree, > Watching one become two. > Little wishes often gestured, > "Come true soon, please do!" > Yet unaware of his presence beneath the same tree. > Though "meeting" seems separated by the ends of the earth, > Around the corner, fate brings us together— > Oh, destiny, destiny!

**This problem uses multiple test cases.** Xinxin has a sequence from $1$ to $n$ and wants to perform the following two operations: **Operation 1**: Delete all elements at odd positions. **Operation 2**: Delete all elements at even positions. After performing $k$ operations, exactly one number remains. Given the sequence of operations, determine the final remaining number.

- The first line contains a positive integer $T$, the number of test cases. - For each test case: - The first line contains two integers $n$ and $k$. - The second line contains $k$ integers representing the operations (1 for Operation 1, 2 for Operation 2).

Output $T$ lines, each containing the answer for the corresponding test case.

### Explanation **Sample Explanation:** For the first test case, the sequence evolves as: $\{1,2,3,4,5\} \to \{2,4\} \to \{4\}$. ### Constraints - For $30\%$ of the data: $n \leq 5 \times 10^5$. - For $100\%$ of the data: - $1 \leq T \leq 10$, - $1 \leq n \leq 10^{18}$. - It is guaranteed that exactly one number remains after $k$ operations for all test cases.