LeetCode -- Sum Root to Leaf Numbers

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public int SumNumbers(TreeNode root) 
    {
        if(root == null){
    		return 0;
    	}
         var ret = new List<string>();
         Sum(root, "",ref ret);
         
         var s = 0;
         for(var i = 0;i < ret.Count; i++){
         	 s += int.Parse(ret[i]);
         }
         
         return s;
    }


private void Sum(TreeNode root, string s,ref List<string> result)
{
	if(root.left == null && root.right == null){
		result.Add(s + root.val);
		return;
	}
	
	if(root.left != null){
		Sum(root.left, s + root.val, ref result);
	}
	if(root.right != null){
		Sum(root.right, s + root.val, ref result);
	}
}
}

LeetCode -- Sum Root to Leaf Numbers

原文：http://blog.csdn.net/lan_liang/article/details/49885323