Package g1701_1800.s1718_construct_the_lexicographically_largest_valid_sequence

Class Solution

java.lang.Object
g1701_1800.s1718_construct_the_lexicographically_largest_valid_sequence.Solution
public class Solution extends java.lang.Object
1718 - Construct the Lexicographically Largest Valid Sequence.

Medium

Given an integer n, find a sequence that satisfies all of the following:

  • The integer 1 occurs once in the sequence.
  • Each integer between 2 and n occurs twice in the sequence.
  • For every integer i between 2 and n, the distance between the two occurrences of i is exactly i.

The distance between two numbers on the sequence, a[i] and a[j], is the absolute difference of their indices, |j - i|.

Return the lexicographically largest sequence_. It is guaranteed that under the given constraints, there is always a solution._

A sequence a is lexicographically larger than a sequence b (of the same length) if in the first position where a and b differ, sequence a has a number greater than the corresponding number in b. For example, [0,1,9,0] is lexicographically larger than [0,1,5,6] because the first position they differ is at the third number, and 9 is greater than 5.

Example 1:

Input: n = 3

Output: [3,1,2,3,2]

Explanation: [2,3,2,1,3] is also a valid sequence, but [3,1,2,3,2] is the lexicographically largest valid sequence.

Example 2:

Input: n = 5

Output: [5,3,1,4,3,5,2,4,2]

Constraints:

  • 1 <= n <= 20

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int[]
    constructDistancedSequence(int n)
     

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • constructDistancedSequence

      public int[] constructDistancedSequence(int n)