判断是否为二叉平衡树c++

struct TreeNode {
	int val;
	TreeNode* left;
	TreeNode* right;
	TreeNode(int x): val(x), left(nullptr), right(nullptr){}
};
class Solution {
public:
	bool isBalanced(TreeNode* root) {
		if (!root)
			return true;
		int ldep = depth(root->left);
		int rdep = depth(root->right);
		if (abs(ldep - rdep) > 1)
			return false;
		return isBalanced(root->left) && isBalanced(root->right);
	}
	int depth(TreeNode* root) {
		if (!root)
			return 0;
		int ldep = depth(root->left);
		int rdep = depth(root->right);
		return ldep >= rdep ? ldep + 1: rdep + 1;
	}
};