CF1437F.Emotional Fishermen

普及/提高-

通过率:0%

AC君温馨提醒

该题目为【codeforces】题库的题目,您提交的代码将被提交至codeforces进行远程评测,并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供,我们无法保证该服务的稳定性,若提交后无反应,请等待一段时间后再进行重试。

题目描述

nn fishermen have just returned from a fishing vacation. The ii -th fisherman has caught a fish of weight aia_i .

Fishermen are going to show off the fish they caught to each other. To do so, they firstly choose an order in which they show their fish (each fisherman shows his fish exactly once, so, formally, the order of showing fish is a permutation of integers from 11 to nn ). Then they show the fish they caught according to the chosen order. When a fisherman shows his fish, he might either become happy, become sad, or stay content.

Suppose a fisherman shows a fish of weight xx , and the maximum weight of a previously shown fish is yy ( y=0y = 0 if that fisherman is the first to show his fish). Then:

  • if x2yx \ge 2y , the fisherman becomes happy;
  • if 2xy2x \le y , the fisherman becomes sad;
  • if none of these two conditions is met, the fisherman stays content.

Let's call an order in which the fishermen show their fish emotional if, after all fishermen show their fish according to this order, each fisherman becomes either happy or sad. Calculate the number of emotional orders modulo 998244353998244353 .

输入格式

The first line contains one integer nn ( 2n50002 \le n \le 5000 ).

The second line contains nn integers a1a_1 , a2a_2 , ..., ana_n ( 1ai1091 \le a_i \le 10^9 ).

输出格式

Print one integer — the number of emotional orders, taken modulo 998244353998244353 .

输入输出样例

  • 输入#1

    4
    1 1 4 9

    输出#1

    20
  • 输入#2

    4
    4 3 2 1

    输出#2

    0
  • 输入#3

    3
    4 2 1

    输出#3

    6
  • 输入#4

    8
    42 1337 13 37 420 666 616 97

    输出#4

    19200
首页