题目描述
Problem Statement
You are given a multiset of positive integers with N elements: $A=\lbrace A_1,A_2,\dots,A_N \rbrace$.
You may repeat the following operation any number of times (possibly zero).
- Choose a positive integer x that occurs at least twice in A. Delete two occurrences of x from A, and add one occurrence of x+1 to A.
Find the number, modulo 998244353, of multisets that A can be in the end.
Input
The input is given from Standard Input in the following format:
N
$A_1 A_2 \dots A_N$
Output
Print the answer.
Constraints
- $1 \le N \le 2 \times 10^5$
- $1 \le A_i \le 2 \times 10^5$
Sample Input 1
4
1 1 2 4
Sample Output 1
3
A can be one of the three multisets $\lbrace 1,1,2,4 \rbrace,\lbrace 2,2,4 \rbrace,\lbrace 3,4 \rbrace$ in the end.
You can make $A = \lbrace 3,4 \rbrace$ as follows.
- Choose x = 1. Delete two 1s from A and add one 2 to $A, making A=\lbrace 2,2,4 \rbrace$.
- Choose x = 2. Delete two 2s from A and add one 3 to $A, making A=\lbrace 3,4 \rbrace$.
Sample Input 2
5
1 2 3 4 5
Sample Output 2
1
Sample Input 3
13
3 1 4 1 5 9 2 6 5 3 5 8 9
Sample Output 3
66
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分