// @Title: 填充每个节点的下一个右侧节点指针 II (Populating Next Right Pointers in Each Node II)
// @Author: qisiii
// @Date: 2024-09-14 23:51:28
// @Runtime: 1 ms
// @Memory: 43.2 MB
// @comment: 
// @flag: 
/*
// Definition for a Node.
class Node {
    public int val;
    public Node left;
    public Node right;
    public Node next;

    public Node() {}
    
    public Node(int _val) {
        val = _val;
    }

    public Node(int _val, Node _left, Node _right, Node _next) {
        val = _val;
        left = _left;
        right = _right;
        next = _next;
    }
};
*/

class Solution {
    public Node connect(Node root) {
        if (root == null) {
            return root;
        }
        Queue<Node> queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            int size = queue.size();
            Node right=null;
            while (size > 0) {
                Node node = queue.poll();
                node.next=right;
                right=node;
                if (node.right != null) {
                    queue.offer(node.right);
                }
                if (node.left != null) {
                    queue.offer(node.left);
                }
                size--;
            }
        }
        return root;
    }
}