面试题39：二叉树的深度

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public int TreeDepth(TreeNode root) {
        return recurse(root, 0);
    }

    private int recurse(TreeNode node, int depth){
        if(node==null){
            return depth;
        }
        int leftDepth = recurse(node.left, depth+1);
        int rightDepth = recurse(node.right, depth+1);
        return leftDepth>rightDepth?leftDepth:rightDepth;
    }
}