Given a binary tree, determine if it is height-balanced.
For this problem, a height-balanced binary tree is defined as:
a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
Example：
[3,9,20,null,null,15,7]
true
[1,2,2,3,3,null,null,4,4]
false
解释下题目：
判断一棵树是不是平衡二叉树
1. 根据树的深度判断
实际耗时：0ms
private boolean isBanlanced = true;
public boolean isBalanced(TreeNode root) {
maxDepth(root);
return isBanlanced;
}
public int maxDepth(TreeNode root) {
if (root == null) {
return 0;
}
int left = maxDepth(root.left);
int right = maxDepth(root.right);
if (Math.abs(left - right) > 1) {
isBanlanced = false;
}
return 1 + Math.max(left, right);
}
思路很简单，就是根据最深子树进行判断呗。
