LeetCode OJ：Maximum Depth of Binary Tree（二叉树最大深度）

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

求二叉树深度，直接看代码：

 /**
  * Definition for a binary tree node.
  * struct TreeNode {
  *     int val;
  *     TreeNode *left;
  *     TreeNode *right;
  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
  * };
  */
 class Solution {
 public:
     int maxDepth(TreeNode* root) {
         if(root == NULL) return ;
         _max = ;
         tranverse(root->left, );
         tranverse(root->right, );
         return _max;
     }
     void tranverse(TreeNode * node, int count)
     {
         if(node == NULL)
             return;
         else{
             if(count +  > _max)
                 _max = count + ;
             tranverse(node->left, count + );
             tranverse(node->right, count + );
         }
     }
 public:
     int _max;
 };

java版的如下所示，上面的递归写的还是太麻烦了，下面的简单很多哈：

 /**
  * Definition for a binary tree node.
  * public class TreeNode {
  *     int val;
  *     TreeNode left;
  *     TreeNode right;
  *     TreeNode(int x) { val = x; }
  * }
  */
 public class Solution {
     public int maxDepth(TreeNode root) {
         if(root == null)
             return 0;
         return tranverse(root, 0);
     }

     public int tranverse(TreeNode root, int val){
         if(root.left == null && root.right == null)
             return val+1;
         int leftDep = 0, rightDep = 0;
         if(root.left != null)
             leftDep = tranverse(root.left, val + 1);
         if(root.right != null)
             rightDep = tranverse(root.right, val + 1);
        return Math.max(leftDep, rightDep);
     }
 }