package LeetCode;

import java.util.LinkedList;
import java.util.Queue;

public class LC_116 {
    static 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;
        }
    }

    ;

    public Node connect(Node root) {
        if (root == null) return null;
        Queue<Node> que = new LinkedList<>();
        que.add(root);
        while (!que.isEmpty()) {
            int len = que.size();
            while (len > 0) {
                Node cur = que.poll();
                if (cur.left != null) que.add(cur.left);
                if (cur.right != null) que.add(cur.right);
                len--;
                if(len == 0) cur.next = null;
                else cur.next = que.peek();
            }
        }
        return root;
    }
}