1123. Lowest Common Ancestor of Deepest Leaves

class Solution {
    public int[] relativeSortArray(int[] arr1, int[] arr2) {
        Map<Integer, Integer> pos = new HashMap<>(arr2.length);
        for (int i = 0; i < arr2.length; ++i) {
            pos.put(arr2[i], i);
        }
        int[][] arr = new int[arr1.length][0];
        for (int i = 0; i < arr.length; ++i) {
            arr[i] = new int[] {arr1[i], pos.getOrDefault(arr1[i], arr2.length + arr1[i])};
        }
        Arrays.sort(arr, (a, b) -> a[1] - b[1]);
        for (int i = 0; i < arr.length; ++i) {
            arr1[i] = arr[i][0];
        }
        return arr1;
    }
}