A16433. Array Collapse
编程题
普及/提高-
知识点
题目描述
You are given an array $[p_1, p_2, \dots, p_n]$ , where all elements are distinct.
You can perform several (possibly zero) operations with it. In one operation, you can choose a contiguous subsegment of $p$ and remove all elements from that subsegment, except for the minimum element on that subsegment. For example, if $p = [3, 1, 4, 7, 5, 2, 6]$ and you choose the subsegment from the $3$ -rd element to the $6$ -th element, the resulting array is $[3, 1, 2, 6]$ .
An array $a$ is called reachable if it can be obtained from $p$ using several (maybe zero) aforementioned operations. Calculate the number of reachable arrays, and print it modulo $998244353$ .
You can perform several (possibly zero) operations with it. In one operation, you can choose a contiguous subsegment of $p$ and remove all elements from that subsegment, except for the minimum element on that subsegment. For example, if $p = [3, 1, 4, 7, 5, 2, 6]$ and you choose the subsegment from the $3$ -rd element to the $6$ -th element, the resulting array is $[3, 1, 2, 6]$ .
An array $a$ is called reachable if it can be obtained from $p$ using several (maybe zero) aforementioned operations. Calculate the number of reachable arrays, and print it modulo $998244353$ .
输入格式
The first line of the input contains one integer $t$ ( $1 \le t \le 10^4$ ) — the number of test cases.
Each test case consists of two lines. The first line contains one integer $n$ ( $1 \le n \le 3 \cdot 10^5$ ). The second line contains $n$ distinct integers $p_1, p_2, \dots, p_n$ ( $1 \le p_i \le 10^9$ ).
Additional constraint on the input: the sum of $n$ over all test cases does not exceed $3 \cdot 10^5$ .
Each test case consists of two lines. The first line contains one integer $n$ ( $1 \le n \le 3 \cdot 10^5$ ). The second line contains $n$ distinct integers $p_1, p_2, \dots, p_n$ ( $1 \le p_i \le 10^9$ ).
Additional constraint on the input: the sum of $n$ over all test cases does not exceed $3 \cdot 10^5$ .
输出格式
For each test case, print one integer — the number of reachable arrays, taken modulo $998244353$ .
输入输出样例
输入 #1
3 2 2 1 4 2 4 1 3 5 10 2 6 3 4
输出 #1
2 6 12