P15867 [MX-X26-T3] "Cfz Round 7" GLACIES
Background
愛してる過去の夜も / The nights of the past that I love.
今じゃ季節に煌めいてゆく / Now they also sparkle in time.
Description
Yuki has a sequence $a$ of length $n$ and a positive integer $m$. It is guaranteed that for all $1 \le i \le n$, $0 \le a_i \lt 2^m$.
For the sequence $a$, Yuki defines its "Fish Value" as:
$$
a_1 \text{ and } a_2 \text{ and } \cdots \text{ and } a_n
$$
That is, the result of bitwise AND over all numbers in the sequence $a$.
Yuki defines one "Bigger" operation as:
- Choose a positive integer $i$ with $i \le n$, and change $a_i$ to $(2 \cdot a_i) \bmod 2^m$.
Yuki wants to perform several "Bigger" operations (possibly $0$ times) to make the "Fish Value" of the sequence $a$ as large as possible.
You need to help her find the minimum number of "Bigger" operations needed to make the "Fish Value" of the sequence $a$ reach its maximum possible value.
Input Format
**This problem has multiple test cases.**
The first line contains two integers $c,t$, representing the subtask index of this test point and the number of test cases. The sample satisfies $c=0$.
Then each test case is given as follows. For each test case:
- The first line contains two integers $n,m$.
- The second line contains $n$ integers $a_1,\dots,a_n$.
Output Format
For each test case, output one line containing one integer, which is the minimum number of "Bigger" operations required to make the "Fish Value" of the sequence $a$ reach the maximum possible value.
Explanation/Hint
### Explanation of Sample 1
For the 1st test case, you can choose $i=1$ and perform the "Bigger" operation $3$ times, then choose $i=2$ and perform it $2$ times, making the sequence $a$ become $\{8,12,8\}$, and the "Fish Value" equals $8$. It can be proven that the maximum possible "Fish Value" of the sequence $a$ is $8$, and at least $5$ operations are required.
For the 2nd test case, no matter what operations you do, the "Fish Value" of the sequence $a$ is always $0$, so the answer is $0$.
### Constraints
Let $\sum n$ denote the sum of $n$ within a single test point.
For all testdata, we have:
- $1 \le t \le 5\cdot10^5$;
- $1 \le n \le 5\cdot 10^5$, $1 \le m \le 60$, $\sum n \le 5\cdot10^5$;
- For all $1 \le i \le n$, $0 \le a_i \lt 2^m$.
**This problem uses bundled tests.**
- Subtask 1 (15 points): $n,m \le 8$, $\sum n \le 8$.
- Subtask 2 (18 points): $n \le 10^3$, $m \le 10$, $\sum n \le 10^3$.
- Subtask 3 (21 points): $n \le 10^4$, $m \le 20$, $\sum n \le 10^4$.
- Subtask 4 (21 points): $n \le 10^5$, $m \le 30$, $\sum n \le 10^5$.
- Subtask 5 (25 points): No special constraints.
Translated by ChatGPT 5