 # Check If N and Its Double Exist

Easy
45.5% Acceptance

In this lab, you will be implementing a function called `checkIfExist` that checks if there exist two indices `i` and `j` in a given array `arr` of integers that satisfy the following conditions:

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

The function should return a boolean value as the result.

## Examples

Example 1:

``````const arr = [10, 2, 5, 3];
checkIfExist(arr); // Output: true
// Explanation: For i = 0 and j = 2, arr[i] == 10 == 2 * 5 == 2 * arr[j]``````

Example 2:

``````const arr = [3, 1, 7, 11];
checkIfExist(arr); // Output: false
// Explanation: There is no i and j that satisfy the conditions.``````

## Constraints

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

In order to successfully pass the challenges, please make sure to follow the instructions as described in the challenges and make use of the ESM import/export wherever needed. The code you write will be evaluated using the evaluation script provided, and ensure that the length of the array `testlog` matches the number of challenges specified in the lab.

Good luck, and happy coding!