题目描述: 解题思路: 此题的思路简单,下面的代码用StringBuilder更加简单,注意最后的结果要反转过来.[LeetCode415]Add Strings的解法和本题一模一样. java代码: public class LeetCode67 { public static void main(String[] args) { String a="11",b="1"; System.out.println(a+"和"+b+"相加的…

题目简述: Given two binary strings, return their sum (also a binary string). For example, a = "11" b = "1" Return "100". 解题思路: class Solution: # @param a, a string # @param b, a string # @return a string def addBinary(self, a, b)…

Given two binary strings, return their sum (also a binary string). For example,a = "11"b = "1"Return "100". 解题思路: 从两个子字符尾部遍历字符: 每次得到新的字符插入结果字符串的头部: 解题步骤: 1.建立返回string.从后向前遍历的idx:idx_a / idx_b.进位量2.循环开始,当idx_a或者idx_b任意不为0时,循环继…

题目描述: 解决思路: 此题较简单,和前面[LeetCode67]方法一样. Java代码: public class LeetCode415 { public static void main(String[] args) { String a="1",b="9"; System.out.println(a+"和"+b+"相加的结果是:"+new Solution().addStrings(a, b)); } } class…

题目描述: 解题思路: 给定两个链表(代表两个非负数),数字的各位以正序存储,将两个代表数字的链表想加获得一个新的链表(代表两数之和). 如(7->2->4->3)(7243) + (5->6->4)(564) = (7->8->0->7)(7807) 此题与[LeetCode2]Add Two Numbers解决思路类似,不同之处在于此题的数字以正序存储,故需要借助栈. Java代码: import java.util.Stack; //public cl…

[LeetCode]199. Binary Tree Right Side View 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode.com/problems/binary-tree-right-side-view/description/ 题目描述: Given a binary tree, imagine yourself standing on the right side of it, return the values of the no…

Difficulty: Hard  More:[目录]LeetCode Java实现 Description https://leetcode.com/problems/binary-tree-postorder-traversal/ Given a binary tree, return the postordertraversal of its nodes' values. Example: Input: [1,null,2,3] 1 \ 2 / 3 Output: [3,2,1] Foll…

[题目] Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with…

[题目] 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. [说明] 不是非常难,思路大家可能都会想到用递归,分别推断左…

链接:https://leetcode.com/tag/binary-search-tree/ [220]Contains Duplicate III (2019年4月20日) (好题) Given an array of integers, find out whether there are two distinct indices i and j in the array such that the absolute difference between nums[i] and nums[…

Find the contiguous subarray within an array (containing at least one number) which has the largest product. For example, given the array [2,3,-2,4],the contiguous subarray [2,3] has the largest product = 6. 找数字连续最大乘积子序列. 思路:这个麻烦在有负数和0,我的方法,如果有0,一切都设…

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. Input: (2 -> 4 -> 3) + (5 -> 6 ->…

Given two binary strings, return their sum (also a binary string).The input strings are both non-empty and contains only characters 1 or 0. Example 1: Input: a = "11", b = "1" Output: "100" Example 2: Input: a = "1010&qu…

Given two binary strings, return their sum (also a binary string). For example,a = "11"b = "1"Return "100". 题解:简单的二进制加法模拟.a,b的最后以为对齐开始进行加法,用carries保存进位,如果加完后最高位还有进位,那么要在结果的最前面加一个1. 代码如下: public class Solution { public String…

string addBinary(string a, string b) { int alen = a.size(); int blen = b.size(); ) return b; ) return a; ; ; ; string res; || j >= || carry > ) { ) carry += a[i--] - '; ) carry += b[j--] - '; res = ( + ') + res; //res不用逆序处理了 carry = carry / ; } retu…

Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 这次的题目要求是得到所有的树. 我的思路:…

随笔一记,留做重温! Flatten Binary Tree to Linked List Given a binary tree, flatten it to a linked list in-place. For example, Given 1 / \ 2 5 / \ \ 3 4 6 The flattened tree should look like: 1 \ 2 \ 3 \ 4 \ 5 \ 6 第一个想法是先序遍历,然后按照访问顺序,添加右结点. public static void…

二连水 题目地址: https://leetcode.com/problems/binary-tree-right-side-view/ 题目内容: Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. For example:Given the following…

Genymotion 新增虚拟设备(模拟器)时,由于网络原因,总是下载失败,如图: 下载失败提示“Unable to create virtual device: Connection timeout occurred”: [提高下载速度和成功率的方法] *如下图,我们选择“Samsung Galaxy S5 - 4.4.4 - API 19 - 1080x1920”进行下载: *打开 C:\Users\用户名\AppData\Local\Genymobile目录 *打开genymotion.l…

Binary Tree Maximum Path Sum Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example:Given the below binary tree, 1 / \ 2 3 Return 6. 树结构显然用递归来解,解题关键: 1.对于每一层递归,只有包含此层树根节点的值才可以返回到上层.否则路径将不连续. 2.…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 DFS BFS 日期 题目描述 Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example: Given binary tree [3,9,20,nul…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 java解法 Python解法 日期 [LeetCode] 题目地址:https://leetcode.com/problems/binary-watch/ Difficulty: Easy 题目描述 A binary watch has 4 LEDs on the top which represent the hours (0-11), and…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 递归 迭代 日期 题目地址:https://leetcode.com/problems/binary-tree-paths/#/description 题目描述 Given a binary tree, return all root-to-leaf paths. Note: A leaf is a node with no children. Ex…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 递归 迭代 日期 题目地址:https://leetcode.com/problems/binary-tree-preorder-traversal/#/description 题目描述 Given a binary tree, return the preorder traversal of its nodes' values. For exampl…

题目描述: You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. Input: (2 -> 4 -> 3) + (5 -> 6…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, given n = 3, there are a total of 5 unique BST's. 1         3     3      2      1     \       /     /      / \      \      3     2     1      1  …

Add Digits Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it. Follow up:Could you do it…

Validate Binary Search Tree Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node c…

Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3   推导出递推公式即可: 对于1个元素来…

Recover Binary Search Tree Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Note:A solution using O(n) space is pretty straight forward. Could you devise a constant space solution? 中序…