62、求根到叶子节点数字之和

题目描述：


很简单的一道题目
代码：

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int sumNumbers(TreeNode root) {
       int sum = 0;
        if(root == null){
        	return sum;
        }
        List<Integer> tem = new ArrayList<>();
        
        get(root,0,tem);
        
        for (Integer integer : tem) {
			sum += integer;
		}
        return sum;
    }

	public static void get(TreeNode root,int sum,List<Integer>tem){
		if(root.left == null && root.right == null){
			sum = sum * 10 + root.val;
			tem.add(sum);
		}
		sum = sum * 10 + root.val;
		if(root.left != null){
		
			get(root.left, sum, tem);
		}
		
		if(root.right != null){
			get(root.right, sum, tem);
		}
		
	}
}