给一个dfs的题解

void dfs(TreeNode* pRoot,int& res,int&dep){
         ++dep;
        if(pRoot->left==nullptr&&pRoot->right==nullptr){res=max(res,dep);--dep;return;}
        if(pRoot->left) dfs(pRoot->left,res,dep);
        if(pRoot->right)dfs(pRoot->right,res,dep);
        --dep;
    }
    int TreeDepth(TreeNode* pRoot)
    {
         int res=0,dep=0;
        if(pRoot==nullptr)return res;
        dfs(pRoot,res,dep);
        return res;

    }