leetcode104 Maximum Depth of Binary Tree

//Solution1:
class Solution {
public:
int maxDepth(TreeNode* root) {
return (root == NULL) ? 0 : max(maxDepth(root->left), maxDepth(root->right)) + 1;
}
};
//Solution2:
struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

struct Node {
TreeNode *t = NULL;
int depth;
Node(TreeNode *tt, int dp) : t(tt), depth(dp) {}
};

class Solution {
public:
int maxDepth(TreeNode* root) {
if(root == NULL)
return 0;
else {
queue<Node> q;
int maxs = 0;
q.push(Node(root, 1));
while(!q.empty()) {
Node tmp = q.front();  q.pop();
if((tmp.t)->left != NULL)
q.push(Node((tmp.t)->left, tmp.depth+1));
if((tmp.t)->right != NULL)
q.push(Node((tmp.t)->right, tmp.depth+1));
maxs = max(tmp.depth, maxs);
}
return maxs;
}
}
};