题解 | #从上往下打印二叉树#

import java.util.*;
import java.util.ArrayList;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
/**

 */
public class Solution {
    public ArrayList<Integer> PrintFromTopToBottom(TreeNode root) {

        ArrayList<Integer> result = new ArrayList<>();
        if(root == null){
            return result;
        }
        Queue<TreeNode> queue = new ArrayDeque<TreeNode>();
        queue.offer(root);
        while(!queue.isEmpty()){
            TreeNode curNode = queue.poll();
            result.add(curNode.val);
            if(curNode.left != null){
                queue.offer(curNode.left);
            }
            if(curNode.right != null){
                queue.offer(curNode.right);
            }
        }
        return result;
    }


}

今天的最后一题，冲冲冲