BinaryTree - 随笔分类 - alau

[Leetcode 108]有序数组转BST二叉搜索树Convert Sorted Array to Binary Search Tree

摘要：题目 https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/ Given an integer array nums where the elements are sorted in ascending or 阅读全文

posted @ 2021-12-05 07:48 alau 阅读(27) 评论(0) 推荐(0)

[Leetcode 235/236]LCA二叉树最近公共祖先Lowest Common Ancestor of a Binary Tree

摘要：题目给定二叉树和两个点，求两点的LCA最近公共祖先 Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of L 阅读全文

posted @ 2021-12-04 02:54 alau 阅读(56) 评论(0) 推荐(0)

[Leetcode 98]判断有效的二叉搜索树Validate Binary Search Tree

摘要：题目 https://leetcode.com/problems/validate-binary-search-tree 判断所给二叉树是否是二叉搜索树二叉搜索树：其值left<root<right *[2,2,2]这种相等的情况也不是搜索树 Given the root of a binary 阅读全文

posted @ 2021-12-03 23:41 alau 阅读(48) 评论(0) 推荐(0)

[Leetcode 104]二叉树最大深度Maximum Depth of Binary Tree

摘要：题目求二叉树的深度，即根节点出发的最长路径上点的个数，即最长路径+1(本身这个点 https://leetcode.com/problems/maximum-depth-of-binary-tree/ Given the root of a binary tree, return its maxi 阅读全文

posted @ 2021-12-03 17:51 alau 阅读(40) 评论(0) 推荐(0)

[Leetcode 103]二叉树zigzag交叉遍历Binary Tree Zigzag Level Order Traversal

摘要：题目二叉树zigzag遍历层次遍历：始终左右 zigzag遍历：每层右左左右交替 Given the root of a binary tree, return the zigzag level order traversal of its nodes' values. (i.e., from 阅读全文

posted @ 2021-11-23 05:34 alau 阅读(108) 评论(0) 推荐(0)

[Leetcode 124]二叉树最大权重路径和 Binary Tree Maximum Path Sum

摘要：题目与543相似，543是求最长路径，这是最大权重求和（路径不一定最长） A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge con 阅读全文

posted @ 2021-11-23 04:45 alau 阅读(249) 评论(0) 推荐(0)

[Leetcode 543]二叉树的直径Diameter of Binary Tree

摘要：题目二叉树的直径，即是求树中任意俩点间的最大距离（深度） Given the root of a binary tree, return the length of the diameter of the tree. The diameter of a binary tree is the len 阅读全文

posted @ 2021-11-23 04:24 alau 阅读(37) 评论(0) 推荐(0)

[Leetcode 102/107]比较

摘要：待阅读全文

posted @ 2021-08-20 18:58 alau 阅读(20) 评论(0) 推荐(0)

[Leetcode 144]二叉树前序遍历Binary Tree Preorder Traversal

摘要：【题目】 Given a binary tree, return the preordertraversal of its nodes' values. Example: 【思路】有参考，好机智，使用堆栈压入右子树，暂时存储。左子树遍历完成后遍历右子树。【代码】阅读全文

posted @ 2018-11-13 18:44 alau 阅读(115) 评论(0) 推荐(0)

[Leetcode 108]有序数组转二叉搜索树Convert Sorted Array to Binary Search Tree

摘要：【题目】给出的升序排序的数组，个数必为奇数，要求形成二叉搜索（平衡）树。【思路】辅助函数fun，[0，len]=>[0,mid-1]+[mid+1,len]。当left>right,返回null。【AC代码】阅读全文

posted @ 2018-11-13 18:01 alau 阅读(115) 评论(0) 推荐(0)

[Leetcode 105]*前序后序遍历形成树

摘要：so basically flag-start is size of the roots left subtree, therefore to get the start of right subtree you gotta get to the start of the first value o 阅读全文

posted @ 2018-11-13 17:40 alau 阅读(178) 评论(0) 推荐(0)

[Leetcode 101]判断对称树 Symmetric Tree

摘要：【题目】 Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is s 阅读全文

posted @ 2018-11-09 18:17 alau 阅读(140) 评论(0) 推荐(0)

[Leetcode 100]判断二叉树相同 Same Tree

摘要：【题目】判断二叉树是否相同。【思路】 check函数。 p==null并且q==null，返回true;（两边完全匹配） p==null或q==null，返回false;(p、q其中一方更短) p.val==q.val，值相同，继续迭代向左向右遍历check(p.left,q.left)&&ch 阅读全文

posted @ 2018-11-09 17:48 alau 阅读(124) 评论(0) 推荐(0)

随笔分类 - BinaryTree

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