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  • [leetcode-110]balanced-binary-tree

    balanced-binary-tree

    (1过)

    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.

    给定一个二叉树,判断它是否是高度平衡的二叉树。

    本题中,一棵高度平衡二叉树定义为:

    一个二叉树每个节点 的左右两个子树的高度差的绝对值不超过1。

    示例 1:

    给定二叉树 [3,9,20,null,null,15,7]

        3
       / 
      9  20
        /  
       15   7

    返回 true 。

    示例 2:

    给定二叉树 [1,2,2,3,3,null,null,4,4]

           1
          / 
         2   2
        / 
       3   3
      / 
     4   4
    

    返回 false 。

    我的解法:

    /**
     * Definition for binary tree
     * public class TreeNode {
     *     int val;
     *     TreeNode left;
     *     TreeNode right;
     *     TreeNode(int x) { val = x; }
     * }
     */
    public class BalancedBinaryTree {
    
        boolean flag = true;
        public boolean isBalanced(TreeNode root) {
            height(root);
            return flag;
        }
        private int height(TreeNode root) {
            if(root == null) {
                return 0;
            }
            int left = height(root.left);
            int right = height(root.right);
            if (Math.abs(left -right) >1) {
                flag = false;
            }
            return Math.max(left,right)+1;
        }
    }
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  • 原文地址:https://www.cnblogs.com/twoheads/p/10563565.html
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