1299.replace-elements-with-greatest-element-on-right-side.py

class Solution:
    def replaceElements(self, arr: List[int]) -> List[int]:
        maxRight = -1
        for i in range(len(arr) - 1, -1, -1):
            curr = arr[i]
            arr[i] = maxRight
            maxRight = max(maxRight, curr)

        return arr