Package g0801_0900.s0873_length_of_longest_fibonacci_subsequence

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    873 - Length of Longest Fibonacci Subsequence\.

    Medium

    A sequence <code>x<sub>1</sub>, x<sub>2</sub>, ..., x<sub>n</sub></code> is Fibonacci-like if:

    • n &gt;= 3

    • <code>x<sub>i</sub> + x<sub>i+1</sub> == x<sub>i+2</sub></code> for all i + 2 &lt;= n

    Given a strictly increasing array arr of positive integers forming a sequence, return the length of the longest Fibonacci-like subsequence of arr. If one does not exist, return 0.

    A subsequence is derived from another sequence arr by deleting any number of elements (including none) from arr, without changing the order of the remaining elements. For example, [3, 5, 8] is a subsequence of [3, 4, 5, 6, 7, 8].

    Example 1:

    Input: arr = 1,2,3,4,5,6,7,8

    Output: 5

    Explanation: The longest subsequence that is fibonacci-like: 1,2,3,5,8.

    Example 2:

    Input: arr = 1,3,7,11,12,14,18

    Output: 3

    Explanation:: The longest subsequence that is fibonacci-like: 1,11,12, 3,11,14 or 7,11,18.

    Constraints:

    • 3 &lt;= arr.length &lt;= 1000

    • <code>1 <= arri< arri + 1<= 10<sup>9</sup></code>

    • 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 lenLongestFibSubseq(IntArray arr)

      • Methods inherited from class java.lang.Object

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