leetcode第104题二叉树深度

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int maxDepth(TreeNode root) {
        if(root==null)return 0;
        if(root.left==null&&root.right==null)return 1;
        int leftDepth = 0;
        int rightDepth = 0;
        if(root.left!=null)leftDepth = maxDepth(root.left);
        if(root.right!=null)rightDepth = maxDepth(root.right);
        
        return leftDepth>rightDepth?leftDepth+1:rightDepth+1;
    }
}