lC116-填充每一个节点的右节点

//leetcode submit region begin(Prohibit modification and deletion)
/*
// 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 {

    List<List<Node>> res = new ArrayList<List<Node>>();
    public Node connect(Node root) {
        if(root == null){
            return null;
        }

        Queue<Node> queue = new LinkedList<Node>();
        queue.offer(root);

        while(!queue.isEmpty()){
            int size = queue.size();
            Node prev = null;

            for (int i = 0; i < size; i++) {
                Node curr = queue.poll();
                if(prev!=null){
                    prev.next = curr;
                }
                prev = curr;
                if(curr.left != null){
                    queue.offer(curr.left);
                }
                if(curr.right != null){
                    queue.offer(curr.right);
                }
            }
        }
        return root;
    }


}
//leetcode submit region end(Prohibit modification and deletion)