Package g2501_2600.s2501_longest_square_streak_in_an_array

Class Solution

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public final class Solution

    2501 - Longest Square Streak in an Array\.

    Medium

    You are given an integer array nums. A subsequence of nums is called a square streak if:

    • The length of the subsequence is at least 2, and

    • after sorting the subsequence, each element (except the first element) is the square of the previous number.

    Return the length of the longest square streak in nums, or return -1 if there is no square streak.

    A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.

    Example 1:

    Input: nums = 4,3,6,16,8,2

    Output: 3

    Explanation: Choose the subsequence 4,16,2. After sorting it, it becomes 2,4,16.

    • 4 = 2 \* 2.

    • 16 = 4 \* 4.

    Therefore, 4,16,2 is a square streak.

    It can be shown that every subsequence of length 4 is not a square streak.

    Example 2:

    Input: nums = 2,3,5,6,7

    Output: -1

    Explanation: There is no square streak in nums so return -1.

    Constraints:

    • <code>2 <= nums.length <= 10<sup>5</sup></code>

    • <code>2 <= numsi<= 10<sup>5</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 longestSquareStreak(IntArray nums)

      • Methods inherited from class java.lang.Object

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