Check If N and Its Double Exist(LeetCode 1346):

Problem

Given an array arr of integers, check if there exist two indices i and j such that :

  • i != j
  • 0 <= i, j < arr.length
  • arr[i] == 2 * arr[j]

 

Example 1:

Input: arr = [10,2,5,3]
Output: true
Explanation: For i = 0 and j = 2, arr[i] == 10 == 2 * 5 == 2 * arr[j]

Example 2:

Input: arr = [3,1,7,11]
Output: false
Explanation: There is no i and j that satisfy the conditions.

 

Constraints:

  • 2 <= arr.length <= 500
  • -103 <= arr[i] <= 103