二叉树求深度

public class TreeNode {
    int val;
    TreeNode leftNode;
    TreeNode rightNode;
    TreeNode(int x) {
        val = x;
    }
}

public class GetDepth {
    public int treeDepth(TreeNode root){
        if(root==null)
            return 0;
        int left = treeDepth(root.leftNode);
        int right = treeDepth(root.rightNode);
        return left > right ? (left+1) : (right+1);

    }

}