【leetcode】SumRoottoLeafNumbers

/**
 * Definition for binary tree
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    private int result=0;
    public int SumNumbers(TreeNode root) {
        if (root==null)
        {
            return 0;
        }
        Solve(root,0);
        return result;
    }
    
    public static void Solve(TreeNode root,int sum)
    {
        if(root.left==null&&root.right==null)
        result+=(sum*10+root.val);
        if(root.left!=null)
        Solve(root.left,sum*10+root.val);
        if(root.right!=null)
        Solve(root.right,sum*10+root.val);
    }
    
}