public class Solution
extends Object
1299 - Replace Elements with Greatest Element on Right Side\.
Easy
Given an array `arr`, replace every element in that array with the greatest element among the elements to its right, and replace the last element with `-1`.
After doing so, return the array.
**Example 1:**
**Input:** arr = [17,18,5,4,6,1]
**Output:** [18,6,6,6,1,-1]
**Explanation:**
- index 0 --> the greatest element to the right of index 0 is index 1 (18).
- index 1 --> the greatest element to the right of index 1 is index 4 (6).
- index 2 --> the greatest element to the right of index 2 is index 4 (6).
- index 3 --> the greatest element to the right of index 3 is index 4 (6).
- index 4 --> the greatest element to the right of index 4 is index 5 (1).
- index 5 --> there are no elements to the right of index 5, so we put -1.
**Example 2:**
**Input:** arr = [400]
**Output:** [-1]
**Explanation:** There are no elements to the right of index 0.
**Constraints:**
* 1 <= arr.length <= 104
* 1 <= arr[i] <= 105