Asterism (Easy Version)

题意翻译

这是问题 E 的简单版本。它与 E2 的唯一区别在于 $n$ 和 $a_i$ 的大小。 Yuzu~~soft~~ 是一个收集糖果的女孩。最初，她有 $x$ 个糖果。有 $n$ 个敌人，编号从 $1$ 到 $n$，第 $i$ 个敌人有 $a_i$ 个糖果。 Yuzu 需要确定一个 $1$ 到 $n$ 的排列 $P$。在此之后，她按照以下规则挑战敌人： - 如果 Yuzu 的糖果不少于编号为 $P_i$ 的敌人的糖果，她会赢得一个糖果。否则，她什么也得不到。 - 得到的糖果加入她拥有糖果的总数量中，可以在下次挑战中使用。 Yuzu 想赢得所有挑战。有多少种排列 $P$？ 然而，这个问题太简单了。设 $f(x)$ 为 Yuzu 初始有 $x$ 个糖果时的，合法的排列总数。给定质数 $p \leq n$，那么你需要求出有多少个 $x$ 使得 $p \nmid f(x)$，其中 $p \nmid f(x)$ 表示 $f(x)$ 不能被 $p$ 整除。 $2 \leq p \leq n \leq 2000,1 \leq a_i \leq 2000$ 翻译 by Meatherm

题目描述

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.

输入输出格式

输入格式

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) $ .

输出格式

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 $ .

输入输出样例

输入样例 #1

3 2
3 4 5

输出样例 #1

1
3

输入样例 #2

4 3
2 3 5 6

输出样例 #2

2
3 4

输入样例 #3

4 3
9 1 1 1

输出样例 #3

0

说明

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 $ .