117.填充每个节点的下一个右侧节点指针-ii.java

/*
 * @lc app=leetcode.cn id=117 lang=java
 *
 * [117] 填充每个节点的下一个右侧节点指针 II
 */

// @lc code=start
/*
// 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();
            for(int i=0;i<size;i++){
                Node node=queue.poll();
                if(i==size-1){
                    node.next=null;
                }else{
                    node.next=queue.peek();
                }
                if(node.left!=null){
                    queue.offer(node.left);
                }
                
                if(node.right!=null){
                    queue.offer(node.right);
                }
            }
        }
        return root;
        
    }
}
// @lc code=end