Asterism (Easy Version)

1000ms

262144K

Description:

This is the easy version of the problem. The difference between versions is the constraints on $$$n$$$ and $$$a_i$$$. You can make hacks only if all versions of the problem are solved.

First, Aoi came up with the following idea for the competitive programming problem:

Yuzu is a girl who collecting candies. Originally, she has $$$x$$$ candies. There are also $$$n$$$ enemies numbered with integers from $$$1$$$ to $$$n$$$. Enemy $$$i$$$ has $$$a_i$$$ candies.

Yuzu is going to determine a permutation $$$P$$$. A permutation is an array consisting of $$$n$$$ distinct integers from $$$1$$$ to $$$n$$$ in arbitrary order. For example, $$$\{2,3,1,5,4\}$$$ is a permutation, but $$$\{1,2,2\}$$$ is not a permutation ($$$2$$$ appears twice in the array) and $$$\{1,3,4\}$$$ is also not a permutation (because $$$n=3$$$ but there is the number $$$4$$$ in the array).

After that, she will do $$$n$$$ duels with the enemies with the following rules:

If Yuzu has equal or more number of candies than enemy $$$P_i$$$, she wins the duel and gets $$$1$$$ candy. Otherwise, she loses the duel and gets nothing.
The candy which Yuzu gets will be used in the next duels.

Yuzu wants to win all duels. How many valid permutations $$$P$$$ exist?

This problem was easy and wasn't interesting for Akari, who is a friend of Aoi. And Akari made the following problem from the above idea:

Let's define $$$f(x)$$$ as the number of valid permutations for the integer $$$x$$$.

You are given $$$n$$$, $$$a$$$ and a prime number $$$p \le n$$$. Let's call a positive integer $$$x$$$ good, if the value $$$f(x)$$$ is not divisible by $$$p$$$. Find all good integers $$$x$$$.

Your task is to solve this problem made by Akari.

Input:

The first line contains two integers $$$n$$$, $$$p$$$ $$$(2 \le p \le n \le 2000)$$$. It is guaranteed, that the number $$$p$$$ is prime (it has exactly two divisors $$$1$$$ and $$$p$$$).

The second line contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ $$$(1 \le a_i \le 2000)$$$.

Output:

In the first line, print the number of good integers $$$x$$$.

In the second line, output all good integers $$$x$$$ in the ascending order.

It is guaranteed that the number of good integers $$$x$$$ does not exceed $$$10^5$$$.

Sample Input:

3 2
3 4 5

Sample Output:

1
3

Sample Input:

4 3
2 3 5 6

Sample Output:

2
3 4

Sample Input:

4 3
9 1 1 1

Sample Output:

Note:

In the first test, $$$p=2$$$.

If $$$x \le 2$$$, there are no valid permutations for Yuzu. So $$$f(x)=0$$$ for all $$$x \le 2$$$. The number $$$0$$$ is divisible by $$$2$$$, so all integers $$$x \leq 2$$$ are not good.
If $$$x = 3$$$, $$$\{1,2,3\}$$$ is the only valid permutation for Yuzu. So $$$f(3)=1$$$, so the number $$$3$$$ is good.
If $$$x = 4$$$, $$$\{1,2,3\} , \{1,3,2\} , \{2,1,3\} , \{2,3,1\}$$$ are all valid permutations for Yuzu. So $$$f(4)=4$$$, so the number $$$4$$$ is not good.
If $$$x \ge 5$$$, all $$$6$$$ permutations are valid for Yuzu. So $$$f(x)=6$$$ for all $$$x \ge 5$$$, so all integers $$$x \ge 5$$$ are not good.

So, the only good number is $$$3$$$.

In the third test, for all positive integers $$$x$$$ the value $$$f(x)$$$ is divisible by $$$p = 3$$$.

Informação

Provedor Codeforces

Código CF1371E1