```
public boolean isBalanced(TreeNode root) {
if(root==null) return true;
int l=depth(root.left);
int r=depth(root.right);
return ((int)Math.abs(l-r)<2)&&isBalanced(root.left) && isBalanced(root.right);
}
static int depth(TreeNode n){
if(n==null) return 0;
return Math.max(depth(n.left),depth(n.right))+1;
}
```