Package g2701_2800.s2787_ways_to_express_an_integer_as_sum_of_powers

Class Solution

java.lang.Object
g2701_2800.s2787_ways_to_express_an_integer_as_sum_of_powers.Solution
public class Solution extends Object
2787 - Ways to Express an Integer as Sum of Powers.

Medium

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 [n1, n2, …, nk] where n = n1x + n2x + … + nkx.

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

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • numberOfWays

      public int numberOfWays(int n, int x)