116. Populating Next Right Pointers in Each Node(二叉樹)

package Recursion;

import java.util.Stack;

public class Connect_116 {
	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) {
		Node pre=null;
		Node cur=root;
		while(cur!=null) {
			while(pre!=null) {
				pre.left.next=pre.right;
				if(pre.next!=null) {
					pre.right.next=pre.next.left;
				}
				pre=pre.next;
			}
			
			pre=cur;
			cur=cur.left;
		}
		return root;
	}

}