Problem
You are given two integers n
and maxValue
, which are used to describe an ideal array.
A 0-indexed integer array arr
of length n
is considered ideal if the following conditions hold:
- Every
arr[i]
is a value from1
tomaxValue
, for0 <= i < n
. - Every
arr[i]
is divisible byarr[i - 1]
, for0 < i < n
.
Return the number of distinct ideal arrays of length n
. Since the answer may be very large, return it modulo 109 + 7
.
Example 1:
Input: n = 2, maxValue = 5 Output: 10 Explanation: The following are the possible ideal arrays: - Arrays starting with the value 1 (5 arrays): [1,1], [1,2], [1,3], [1,4], [1,5] - Arrays starting with the value 2 (2 arrays): [2,2], [2,4] - Arrays starting with the value 3 (1 array): [3,3] - Arrays starting with the value 4 (1 array): [4,4] - Arrays starting with the value 5 (1 array): [5,5] There are a total of 5 + 2 + 1 + 1 + 1 = 10 distinct ideal arrays.
Example 2:
Input: n = 5, maxValue = 3 Output: 11 Explanation: The following are the possible ideal arrays: - Arrays starting with the value 1 (9 arrays): - With no other distinct values (1 array): [1,1,1,1,1] - With 2nd distinct value 2 (4 arrays): [1,1,1,1,2], [1,1,1,2,2], [1,1,2,2,2], [1,2,2,2,2] - With 2nd distinct value 3 (4 arrays): [1,1,1,1,3], [1,1,1,3,3], [1,1,3,3,3], [1,3,3,3,3] - Arrays starting with the value 2 (1 array): [2,2,2,2,2] - Arrays starting with the value 3 (1 array): [3,3,3,3,3] There are a total of 9 + 1 + 1 = 11 distinct ideal arrays.
Constraints:
2 <= n <= 104
1 <= maxValue <= 104