public boolean isBalanced(TreeNode root) {
if (root==null)
return true;
int leftDepth = maxDepth(root.left);
int rightDepth = maxDepth(root.right);
if (Math.abs(leftDepth - rightDepth) > 1) {
return false;
}
return isBalanced(root.left) && isBalanced(root.right);
}
//获取二叉树的深度
public int maxDepth(TreeNode root) {
if (root==null)
return 0;
return Math.max(maxDepth(root.left), maxDepth(root.right))+1;
}