class Solution {
public:
    vector<int> replaceElements(vector<int>& arr) {
        int len = arr.size();
        vector<int> t(len);
        if (!len) return t;
        t[len - 1] = arr[len - 1];
        for (int i = len - 2; i >= 0; i--)
            t[i] = t[i+1] > arr[i] ? t[i+1] : arr[i];
        vector<int> ret(len);
        ret[len - 1] = -1;
        for (int i = len - 2; i >= 0; i--) 
            ret[i] = t[i+1];
        return ret;
    }
};