[LeetCode] 814. Binary Tree Pruning

yedf 发布于2019-08-16 13:33 / 2249人阅读

Problem

We are given the head node root of a binary tree, where additionally every node"s value is either a 0 or a 1.

Return the same tree where every subtree (of the given tree) not containing a 1 has been removed.

(Recall that the subtree of a node X is X, plus every node that is a descendant of X.)

Example 1:
Input: [1,null,0,0,1]
Output: [1,null,0,null,1]

Explanation:
Only the red nodes satisfy the property "every subtree not containing a 1".
The diagram on the right represents the answer.

Example 2:
Input: [1,0,1,0,0,0,1]
Output: [1,null,1,null,1]

Example 3:
Input: [1,1,0,1,1,0,1,0]
Output: [1,1,0,1,1,null,1]

Solution

class Solution {
    public TreeNode pruneTree(TreeNode root) {
        if (root == null) return null;
        root.left = pruneTree(root.left);
        root.right = pruneTree(root.right);
        if (root.left == null && root.right == null && root.val == 0) return null;
        return root;
    }
}

私有云服务器托管 binary-tree binary-search-tree Pruning LeetCode

文章版权归作者所有，未经允许请勿转载,若此文章存在违规行为，您可以联系管理员删除。

转载请注明本文地址：https://www.ucloud.cn/yun/71931.html

[LintCode/LeetCode] Binary Tree Pruning

Problem Binary Tree PruningWe are given the head node root of a binary tree, where additionally every nodes value is either a 0 or a 1. Return the same tree where every subtree (of the given tree) not...

rockswang 2019-08-16 12:37 评论0 收藏0
LeetCode 606. Construct String from Binary Tree 二叉

摘要：题意从一颗二叉树转为带括号的字符串。这题是的姊妹题型，该题目的解法在这里解法。 LeetCode 606. Construct String from Binary Tree You need to construct a string consists of parenthesis and integers from a binary tree with the preorder t...

mikyou 2019-08-16 13:31 评论0 收藏0
LeetCode 536. Construct Binary Tree from String 从带

摘要：题意从一个带括号的字符串，构建一颗二叉树。其中当而时，展示为一个空的括号。同时要考虑负数的情况，所以在取数字的时候，必须注意所在位置。遇到则从栈中出元素。最后中的元素就是，返回栈顶元素即可。 LeetCode 536. Construct Binary Tree from String You need to construct a binary tree from a string ...

tabalt 2019-08-16 13:31 评论0 收藏0
LeetCode 110 Balanced Binary Tree 平衡二叉树

摘要：题意判断一颗二叉树是否是平衡二叉树，平衡二叉树的定义为，每个节点的左右子树深度相差小于这是和求最大深度的结合在一起，可以考虑写个函数找到拿到左右子树的深度，然后递归调用函数判断左右子树是否也是平衡的，得到最终的结果。 LeetCode 110 Balanced Binary Tree Given a binary tree, determine if it is height-bala...

anquan 2019-08-16 13:28 评论0 收藏0
[LeetCode-Tree]Binary Tree Inorder & Preorder

摘要：代码解题思路先序遍历，同样用迭代实现，借助栈。先将根节点入栈先序遍历，所以直接出根节点因为顺序是根，左节点，右节点，所以我们在压栈的时候要先压右节点，再压左节点。所以我们自定义了一个类，添加了的属性，来表明该节点是否已经被访问过了。 Binary Tree Inorder TraversalGiven a binary tree, return the inorder traversa...

taowen 2019-08-16 10:26 评论0 收藏0