#P1319. Extreme Extension

Extreme Extension

题目描述

For an array b b of n n integers, the extreme value of this array is the minimum number of times (possibly, zero) the following operation has to be performed to make b b non-decreasing:

  • Select an index i i such that 1ib 1 \le i \le |b| , where b |b| is the current length of b b .
  • Replace bi b_i with two elements x x and y y such that x x and y y both are positive integers and x+y=bi x + y = b_i .
  • This way, the array b b changes and the next operation is performed on this modified array.

For example, if b=[2,4,3] b = [2, 4, 3] and index 2 2 gets selected, then the possible arrays after this operation are [2,1,3,3] [2, \underline{1}, \underline{3}, 3] , [2,2,2,3] [2, \underline{2}, \underline{2}, 3] , or [2,3,1,3] [2, \underline{3}, \underline{1}, 3] . And consequently, for this array, this single operation is enough to make it non-decreasing: $ [2, 4, 3] \rightarrow [2, \underline{2}, \underline{2}, 3] $ .

It's easy to see that every array of positive integers can be made non-decreasing this way.

YouKn0wWho has an array a a of n n integers. Help him find the sum of extreme values of all nonempty subarrays of a a modulo 998244353 998\,244\,353 . If a subarray appears in a a multiple times, its extreme value should be counted the number of times it appears.

An array d d is a subarray of an array c c if d d can be obtained from c c by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end.

输入格式

The first line contains a single integer t t ( 1t10000 1 \le t \le 10\,000 ) — the number of test cases.

The first line of each test case contains a single integer n n ( 1n105 1 \le n \le 10^5 ).

The second line of each test case contains n n integers a1,a2,,an a_1, a_2, \ldots, a_n ( 1ai105 1 \le a_i \le 10^5 ).

It is guaranteed that the sum of n n over all test cases doesn't exceed 105 10^5 .

输出格式

For each test case, print a single integer — the sum of extreme values of all subarrays of a a modulo 998244353 998\,244\,353 .

4
3
5 4 3
4
3 2 1 4
1
69
8
7264 40515 28226 92776 35285 21709 75124 48163
5
9
0
117

提示

Let f(l,r) f(l, r) denote the extreme value of [al,al+1,,ar] [a_l, a_{l+1}, \ldots, a_r] .

In the first test case,

  • f(1,3)=3 f(1, 3) = 3 , because YouKn0wWho can perform the following operations on the subarray [5,4,3] [5, 4, 3] (the newly inserted elements are underlined): $ [5, 4, 3] \rightarrow [\underline{3}, \underline{2}, 4, 3] \rightarrow [3, 2, \underline{2}, \underline{2}, 3] \rightarrow [\underline{1}, \underline{2}, 2, 2, 2, 3] $ ;
  • f(1,2)=1 f(1, 2) = 1 , because $ [5, 4] \rightarrow [\underline{2}, \underline{3}, 4] $ ;
  • f(2,3)=1 f(2, 3) = 1 , because $ [4, 3] \rightarrow [\underline{1}, \underline{3}, 3] $ ;
  • f(1,1)=f(2,2)=f(3,3)=0 f(1, 1) = f(2, 2) = f(3, 3) = 0 , because they are already non-decreasing.

So the total sum of extreme values of all subarrays of a=3+1+1+0+0+0=5 a = 3 + 1 + 1 + 0 + 0 + 0 = 5 .