110. Balanced Binary Tree

最新推荐文章于 2022-07-18 20:53:17 发布

Maggie_2015

最新推荐文章于 2022-07-18 20:53:17 发布

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本文链接：https://blog.youkuaiyun.com/Maggie_2015/article/details/50630569

本文介绍了一种用于判断二叉树是否为高度平衡的方法。高度平衡二叉树定义为对于每个节点，其两个子树的深度之差不超过1。通过递归方式计算树的深度并检查是否满足平衡条件。

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.

 public boolean isBalanced(TreeNode root) {
        if(root == null) return true;
        return depth(root) == -1 ? false:true;
    }
    private int depth(TreeNode root) {    //返回-1代表不平衡；返回正整数代表树的最大高度
        if(root == null) return 0;
        int left = depth(root.left);
        if(left == -1) return -1;
        int right = depth(root.right);
        if(right == -1) return -1;
        if(right - left > 1 || right -left < -1) return -1; //左右子树不平衡
        return right >= left ? right+1:left+1;
    }