剑指offer---二叉树的深度

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};*/
class Solution
 {
public:
    int TreeDepth(TreeNode* pRoot)
    {
        if(pRoot==NULL)
        {
            return 0;
        }
        
        int leftdepth=TreeDepth(pRoot->left);
        int rightdepth=TreeDepth(pRoot->right);
        
        return(leftdepth<rightdepth?rightdepth+1:leftdepth+1);
    }
};