1648B · Integral Array

Problem: You are given an array $a$ of $n$ positive integers numbered from $1$ to $n$. Let's call an array integral if for any two, not necessarily different, numbers $x$ and $y$ from this array, $x \ge y$, the number $\left \lfloor \frac{x}{y} \right \rfloor$ ($x$ divided by $y$ with rounding down) is also in this array.

You are guaranteed that all numbers in $a$ do not exceed $c$. Your task is to check whether this array is integral.

Input Format: The input consists of multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 10^4$) — the number of test cases. Description of the test cases follows.

The first line of each test case contains two integers $n$ and $c$ ($1 \le n \le 10^6$, $1 \le c \le 10^6$) — the size of $a$ and the limit for the numbers in the array.

The second line of each test case contains $n$ integers $a_1$, $a_2$, ..., $a_n$ ($1 \le a_i \le c$) — the array $a$.

Let $N$ be the sum of $n$ over all test cases and $C$ be the sum of $c$ over all test cases. It is guaranteed that $N \le 10^6$ and $C \le 10^6$.

Output Format: For each test case print Yes if the array is integral and No otherwise.

Note: In the first test case it is easy to see that the array is integral:

• $\left \lfloor \frac{1}{1} \right \rfloor = 1$, $a_1 = 1$, this number occurs in the arry
• $\left \lfloor \frac{2}{2} \right \rfloor = 1$
• $\left \lfloor \frac{5}{5} \right \rfloor = 1$
• $\left \lfloor \frac{2}{1} \right \rfloor = 2$, $a_2 = 2$, this number occurs in the array
• $\left \lfloor \frac{5}{1} \right \rfloor = 5$, $a_3 = 5$, this number occurs in the array
• $\left \lfloor \frac{5}{2} \right \rfloor = 2$, $a_2 = 2$, this number occurs in the array

Thus, the condition is met and the array is integral.

In the second test case it is enough to see that

$\left \lfloor \frac{7}{3} \right \rfloor = \left \lfloor 2\frac{1}{3} \right \rfloor = 2$, this number is not in $a$, that's why it is not integral.

In the third test case $\left \lfloor \frac{2}{2} \right \rfloor = 1$, but there is only $2$ in the array, that's why it is not integral.