{leetcode}/problems/ways-to-express-an-integer-as-sum-of-powers/[LeetCode - 2787. Ways to Express an Integer as Sum of Powers ^]
Given two positive integers n and x.
Return the number of ways _`n` can be expressed as the sum of the `xth power of unique positive integers, in other words, the number of sets of unique integers [n<sub>1</sub>, n<sub>2</sub>, …, n<sub>k</sub>]` where `n = n<sub>1</sub>x + n<sub>2</sub>x + … + n<sub>k</sub>x`._
Since the result can be very large, return it modulo 109 + 7.
For example, if n = 160 and x = 3, one way to express n is n = 23 + 33 + 53.
Example 1:
Input: n = 10, x = 2 Output: 1 Explanation: We can express n as the following: n = 32 + 12 = 10. It can be shown that it is the only way to express 10 as the sum of the 2nd power of unique integers.
Example 2:
Input: n = 4, x = 1 Output: 2 Explanation: We can express n in the following ways: - n = 41 = 4. - n = 31 + 11 = 4.
Constraints:
-
1 ⇐ n ⇐ 300 -
1 ⇐ x ⇐ 5