public class BalancedBinaryTree {

public boolean isBalanced(TreeNode root) {

if(root == null) return true;

if(Math.abs(height(root.left) - height(root.right)) > 1) return false;

if(!isBalanced(root.left) || !isBalanced(root.right)) return false;

return true;

}

private int height(TreeNode root){

if(root == null) return 0;

return Math.max(height(root.left), height(root.right)) + 1;

}

public static void main(String[] args) {

BalancedBinaryTree tree = new BalancedBinaryTree();

TreeNode root = new TreeNode(5);

TreeNode node1 = new TreeNode(4);

TreeNode node2 = new TreeNode(8);

TreeNode node3 = new TreeNode(11);

TreeNode node4 = new TreeNode(13);

TreeNode node5 = new TreeNode(4);

TreeNode node6 = new TreeNode(7);

TreeNode node7 = new TreeNode(2);

TreeNode node8 = new TreeNode(1);

root.left = node1;

root.right = node2;

node1.left = node3;

node2.left = node4;

node2.right = node5;

node3.left = node6;

node3.right = node7;

node5.right = node8;

System.out.println(tree.isBalanced(root));

}

}