public int[] computeDepth(int tree[]) {
    int[] depth = new int[tree.length];

    depth[0] = 0;
    for (int index=1; index < tree.length; index++) {

        depth[index] = 1;

        int parentIndex = tree[index];
        while (parentIndex != 0) {

            parentIndex = tree[parentIndex];
            depth[index]++;
        }
    }

    return depth;
}