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 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 and Description
Solution()

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Detail

Solution

public Solution()

Method Detail

constructDistancedSequence

public int[] constructDistancedSequence(int n)