Package g0501_0600.s0526_beautiful_arrangement

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    526 - Beautiful Arrangement.

    Medium

    Suppose you have n integers labeled 1 through n. A permutation of those n integers perm ( 1-indexed ) is considered a beautiful arrangement if for every i (1 <= i <= n), either of the following is true:

    • perm[i] is divisible by i.

    • i is divisible by perm[i].

    Given an integer n, return the number of the beautiful arrangements that you can construct.

    Example 1:

    Input: n = 2

    Output: 2

    Explanation:

    The first beautiful arrangement is 1,2:

    • perm1 = 1 is divisible by i = 1

    • perm2 = 2 is divisible by i = 2

    The second beautiful arrangement is 2,1:

    • perm1 = 2 is divisible by i = 1

    • i = 2 is divisible by perm2 = 1

    Example 2:

    Input: n = 1

    Output: 1

    Constraints:

    • 1 <= n <= 15

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer countArrangement(Integer n)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait