Balanced Binary Tree.cpp

class Solution {
public:
    bool isBalanced(TreeNode* root) {
        // If the tree is empty, we can say it’s balanced...
        if (root == NULL)  return true;
        // Height Function will return -1, when it’s an unbalanced tree...
		if (Height(root) == -1)  return false;
		return true;
	}
    // Create a function to return the “height” of a current subtree using recursion...
	int Height(TreeNode* root) {
        // Base case...
		if (root == NULL)  return 0;
        // Height of left subtree...
		int leftHeight = Height(root->left);
        // Height of height subtree...
		int rightHight = Height(root->right);
        // In case of left subtree or right subtree unbalanced or their heights differ by more than ‘1’, return -1...
		if (leftHeight == -1 || rightHight == -1 || abs(leftHeight - rightHight) > 1)  return -1;
        // Otherwise, return the height of this subtree as max(leftHeight, rightHight) + 1...
		return max(leftHeight, rightHight) + 1;
    }
};