https://leetcode.com/problems/check-if-n-and-its-double-exist/description/?envType=daily-question&envId=2024-12-12
Given an array arr of integers, check if there exist two indices i and j such that :
i != j0 <= i, j < arr.lengtharr[i] == 2 * arr[j]Example 1:
Example 2:
Input: arr = [10,2,5,3]
Output: true
Explanation: For i = 0 and j = 2, arr[i] == 10 == 2 * 5 == 2 * arr[j]
Input: arr = [3,1,7,11]
Output: false
Explanation: There is no i and j that satisfy the conditions.
Constraints:
2 <= arr.length <= 500103 <= arr[i] <= 103