[leetcode]Maximum Depth of Binary Tree

简单题。顺手就写出来了。

public class Solution {

    public int maxDepth(TreeNode root) {

        // Start typing your Java solution below

        // DO NOT write main() function        

        if (root == null) return 0;

        if (root.left == null && root.right == null) return 1;

        int lmax = maxDepth(root.left) + 1;

        int rmax = maxDepth(root.right) + 1;

        return Math.max(lmax, rmax);       

    }

}