判断一颗树是否是平衡二叉树

思路很简单，树的最大高度和最小高度之差不能超过1.

The idea is very simple, the difference of minimum height and the maximum height should not exceed 1.

struct Node{
	Node* left;
	Node* right;
};
int MaxHeight(Node* root)
{
	if (root == NULL)
	{
		return 0;
	}
	return 1+max(MaxHeight(root->left),MaxHeight(root->right));
}
int MinHeight(Node *root)
{
	if (root == NULL)
	{
		return 0;
	}
	return 1+min(MinHeight(root->left),MinHeight(root->right));
}
bool IsBalancde(Node * root)
{
	if (root == NULL)
	{
		return true;
	}
	return (MaxHeight(root) - MinHeight(root))<= 1;

}