class Solution {

public:

	bool ans;

	int getHeight(TreeNode *root) {

		if(!ans)

			return 0;

		if(root == NULL)

			return 0;

		int lt = 0, rt = 0;

		if(root->left&&ans) {

			lt = 1+getHeight(root->left);

		}

		if(root->right&&ans)

			rt = 1 + getHeight(root->right);

		if(abs(lt-rt)>1)

			ans = false;

		return max(lt, rt);

	}

	bool isBalanced(TreeNode *root) {

        ans = true;

		if(root == NULL)

			return true;

		getHeight(root);

		return ans;

    }

};