题目描述
Problem Statement
Given are a sequence of $N positive integers A_1, A_2, \ldots, A_N$ and another positive integer S.
For a non-empty subset T of the set ${1, 2, \ldots , N$ }, let us define f(T) as follows:
- f(T) is the number of different non-empty subsets ${x_1, x_2, \ldots , x_k$} of T$A_{x_1}+A_{x_2}+\cdots +A_{x_k} = S$.
Find the sum of f(T) over all 2^N-1 subsets T of ${1, 2, \ldots , N$ }. Since the sum can be enormous, print it modulo 998244353.
Input
Input is given from Standard Input in the following format:
N S
A_1 A_2 ... A_N
Output
Print the sum of f(T) modulo 998244353.
Constraints
- All values in input are integers.
- $1 \leq N \leq 3000$
- $1 \leq S \leq 3000$
- $1 \leq A_i \leq 3000$
Sample Input 1
3 4
2 2 4
Sample Output 1
6
For each T, the value of f(T) is shown below. The sum of these values is 6.
- f({1}) = 0
- f({2}) = 0
- f({3}) = 1 (One subset {3} satisfies the condition.)
- f({1, 2}) = 1 ({1, 2})
- f({2, 3}) = 1 ({3})
- f({1, 3}) = 1 ({3})
- f({1, 2, 3}) = 2 ({1, 2}, {3})
Sample Input 2
5 8
9 9 9 9 9
Sample Output 2
0
Sample Input 3
10 10
3 1 4 1 5 9 2 6 5 3
Sample Output 3
3296
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分