/*
// Definition for a QuadTree node.
class Node {
    public boolean val;
    public boolean isLeaf;
    public Node topLeft;
    public Node topRight;
    public Node bottomLeft;
    public Node bottomRight;

    public Node() {}

    public Node(boolean _val,boolean _isLeaf,Node _topLeft,Node _topRight,Node _bottomLeft,Node _bottomRight) {
        val = _val;
        isLeaf = _isLeaf;
        topLeft = _topLeft;
        topRight = _topRight;
        bottomLeft = _bottomLeft;
        bottomRight = _bottomRight;
    }
};
*/
class Solution {
    public Node intersect(Node q1, Node q2) {
        if (q1.isLeaf) return (q1.val ? q1 : q2);
        if (q2.isLeaf) return (q2.val ? q2 : q1);
        q1.topLeft = intersect(q1.topLeft, q2.topLeft);
        q1.topRight = intersect(q1.topRight, q2.topRight);
        q1.bottomLeft = intersect(q1.bottomLeft, q2.bottomLeft);
        q1.bottomRight = intersect(q1.bottomRight, q2.bottomRight);
        if (q1.topLeft.isLeaf && q1.topRight.isLeaf && q1.bottomLeft.isLeaf && q1.bottomRight.isLeaf) {
            if (q1.topLeft.val && q1.topRight.val && q1.bottomLeft.val && q1.bottomRight.val) {
                q1.isLeaf = true;
                q1.val = true;
                return q1;
            }
            if (!(q1.topLeft.val || q1.topRight.val || q1.bottomLeft.val || q1.bottomRight.val)) {
                q1.isLeaf = true;
                q1.val = false;
                return q1;
            }
        }
        return q1;
    }
}