# 1299. Replace Elements with Greatest Element on Right Side
###### tags: `Leetcode` `Easy`
Link: https://leetcode.com/problems/replace-elements-with-greatest-element-on-right-side/
## 思路 $O(N)$ $O(1)$
## Code

class Solution {
    public int[] replaceElements(int[] arr) {
        int max = arr[arr.length-1];
        arr[arr.length-1] = -1;
        for(int i = arr.length-2;i >= 0;i--){
            int prevMax = max;
            max = Math.max(arr[i], max);
            arr[i] = prevMax;
        }
        return arr;
    }
}