LeetCode - 110. 平衡二叉树

import java.util.*;

class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) { val = x; }
}
class Solution {

private int deep(TreeNode root) {
if (Objects.isNull(root)) {
return 0;
}

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

public boolean isBalanced(TreeNode root) {
if (Objects.isNull(root)) {
return true;
}

return Math.abs(deep(root.left) - deep(root.right)) <= 1 && isBalanced(root.left) && isBalanced(root.right);
}
}