输入一颗二叉树的根节点，求二叉树的深度

1、题目

2、思路

class Solution {
public:
    int TreeDepth(TreeNode* pRoot)
    {
        if(pRoot == nullptr)
            return 0;
        int left = TreeDepth(pRoot->left);
        int right = TreeDepth(pRoot->right);

        return (left>right) ? (left+1) : (right+1);

    }
};