public static int SumNumbers(TreeNode root)
{
int res = 0;
if (root == null) return res;
dfs(root, 0, ref res);
return res;
}
static void Main(string[] args)
{
TreeNode root = new TreeNode(1);
root.left = new TreeNode(2);
root.right = new TreeNode(3);
root.left.left = new TreeNode(3);
int result = SumNumbers(root);
Console.Write("Output is " + result);
}
public static void dfs(TreeNode root, int cur, ref int res)
{
TreeNode l = root.left;
TreeNode r = root.right;
if (l == null && r == null)
{
cur = cur * 10 + root.val;
res += cur;
return;
}
cur=cur*10+root.val;
if(l!=null)
dfs(l,cur, ref res);
if(r!=null)
dfs(r,cur, ref res);
}