1299. Replace Elements with Greatest Element on Right Side-将每个元素替换为右侧最大元素

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 <= 10^4
• 1 <= arr[i] <= 10^5

Solution in python:

class Solution:
    def replaceElements(self, arr: List[int]) -> List[int]:
        result = [-1]
        for v in arr[::-1]:
            if v > result[0]:
                result.insert(0, v)
            else:
                result.insert(0, result[0])
        result.pop(0)
        return result