老年退役选手的 LeetCode 休闲之旅 前言 不知不觉两年多的大学时光悄然流逝,浑浑噩噩的状态似乎从来没有离开过自己. 这两年刷题似乎一直是常态.在退役之后的现在,深感有些东西一段时间没有接触,很容易就变得陌生,遂萌生了刷 LeetCode 的想法,不知这一次能维持多久,谨以此记录来不时地警醒自己. -- 记于2018年寒假 LeetCode之旅 一开始的计划是先不考虑tag,把题目限制在 1~200 题,刷题的顺序是按照难度(Easy-Medium-Hard),题号(1~200). 结果一…

准备Google面试的总结 - 知乎 https://zhuanlan.zhihu.com/p/40866467 [不周山之算法与数据结构]壹 总览 | 小土刀 https://wdxtub.com/2016/01/22/programmer-startline-1/ Leetcode 算法题解 - 细语呢喃 https://www.hrwhisper.me/leetcode-algorithm-solution/ Leetcode 分类顺序第二版 https://cspiration.com/…

126. Word Ladder II 题目 Given two words (beginWord and endWord), and a dictionary's word list, find all shortest transformation sequence(s) from beginWord to endWord, such that: Only one letter can be changed at a time Each transformed word must exist…

112. Path Sum Easy Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. Note: A leaf is a node with no children. Example: Given the below binary tree and …

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 22: Generate Parentheseshttps://oj.leetcode.com/problems/generate-parentheses/ Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For exa…

2017/11/22 Leetcode 日记 136. Single Number Given an array of integers, every element appears twice except for one. Find that single one. class Solution { public: int singleNumber(vector<int>& nums) { int len = nums.size(); ]; ; i < len; i++){…

Leetcode之回溯法专题-22. 括号生成(Generate Parentheses) 给出 n 代表生成括号的对数,请你写出一个函数,使其能够生成所有可能的并且有效的括号组合. 例如,给出 n = 3,生成结果为: [ "((()))", "(()())", "(())()", "()(())", "()()()"] 分析:给定一个n,生成所有可能的括号组合. 举个例子,n=3,需要生成三个括号,那最…

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ "((()))", "(()())", "(())()", "()(())", "()()()" ]   …

22. 括号生成 22. Generate Parentheses 题目描述 给出 n 代表生成括号的对数,请你写出一个函数,使其能够生成所有可能的并且有效的括号组合. 例如,给出 n = 3,生成结果为: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] LeetCode22. Generate Parentheses中等回溯算法 Java 实现 i…

22. 括号生成 给出 n 代表生成括号的对数,请你写出一个函数,使其能够生成所有可能的并且有效的括号组合. 例如,给出 n = 3,生成结果为: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] 来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/generate-parentheses 著作权归领…

https://leetcode.com/problems/generate-parentheses/ Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: "((()))", "(()())", "(())()&q…

I thought I know Python... Actually , I know nothing... 这个题真想让人背下来啊,每一句都很帅!!! Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ "((()))", "…

22. 242. Valid Anagram(由颠倒字母顺序而构成的字) Given two strings s and t, write a function to determine if t is an anagram of s. For example, s = "anagram", t = "nagaram", return true. s = "rat", t = "car", return false. Note…

一天一道LeetCode (一)题目 Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: "((()))", "(()())", "(())()", "()(())", "(…

非常好的一道题.一开始的思想是这样的,先把n对括号按照某一顺序生成一个string,然后用全排列算法生成所有可能,然后利用stack写一段判断括号是否匹配的字符串,匹配的假如结果中.不过会超时.因为全排列的复杂度略高,阶乘级别.而对于阶乘函数和指数函数的复杂度,显然是阶乘函数高,指数每次乘一个相同的数(这里是2),而阶乘每次乘一个更大的数.全排列算法复杂度会很大,超时也就不奇怪了.所以对于n对括号,有2n个位置,每个位置都有两种选择,所以一共是4的n次幂.leetcode显示超时也是从n=5开始…

题目链接 : https://leetcode.com/problems/generate-parentheses/?tab=Description   给一个整数n,找到所有合法的 () pairs    For example, given n = 3, a solution set is: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] 递归程…

1. 原题链接 https://leetcode.com/problems/generate-parentheses/description/ 2. 题目要求 给出一个正整数n,请求出由n对合法的圆括号组合 例如,n = 3,答案: 3. 解题思路 采用递归的方法:给定的整数为n,定义一个字符串类型变量str用来保存组合."("的个数记为left,")"的个数记为right,当left<n时或者right<left时都进行递归. 当str的长度lengt…

171. Excel表列序号 171. Excel Sheet Column Number 题目描述 给定一个 Excel 表格中的列名称,返回其相应的列序号. 每日一算法2019/5/25Day 22LeetCode171. Excel Sheet Column Number 例如, A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 28 ... 示例 1: 输入: "A" 输出: 1 示例 2: 输入…

题目 给出 n 代表生成括号的对数,请你写出一个函数,使其能够生成所有可能的并且有效的括号组合. 例如,给出 n = 3,生成结果为: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] 来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/generate-parentheses 著作权归领扣网络所有.…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 个人公众号:负雪明烛 本文关键词:括号, 括号生成,题解,leetcode, 力扣,Python, C++, Java 目录 题目描述 题目大意 解题方法 回溯法 日期 题目地址:https://leetcode.com/problems/generate-parentheses/description/ 题目描述 Given n pairs of parentheses, write…

剑指 Offer 22. 链表中倒数第k个节点 题意 输入一个链表,输出该链表中倒数第k个节点.为了符合大多数人的习惯,本题从1开始计数,即链表的尾节点是倒数第1个节点. ​ 例如,一个链表有 6 个节点,从头节点开始,它们的值依次是 1.2.3.4.5.6,则这个链表的倒数第 3 个节点是值为 4 的节点. ​ 链表节点的定义如下: struct ListNode { int val; ListNode* next; ListNode(int x) : val(x), next(NULL) {…

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] pub…

Distinct Subsequences Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without di…

题目描述: Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: "((()))", "(()())", "(())()", "()(())", "()()()" 解…

problem:Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 先合并两个list,再根据归并排序的方法递归合并.假设总共有k个list,每个list的最大长度是n,那么运行时间满足递推式T(k) = 2T(k/2)+O(n*k).根据主定理,可以算出算法的总复杂度是O(nklogk).空间复杂度的话是递归栈的大小O(logk). /** * De…

66. Plus One 题目 这题很简单,直接代码: class Solution { public: vector<int> plusOne(vector<int> &digits) { // IMPORTANT: Please reset any member data you declared, as // the same Solution instance will be reused for each test case. ; vector<int>…

题目: You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security system connected and it will a…

题目链接:https://leetcode-cn.com/problems/generate-parentheses/ 题目描述: 给出 n 代表生成括号的对数,请你写出一个函数,使其能够生成所有可能的并且有效的括号组合. 示例: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] 思路: 回溯算法 递归过程中,通过左括号和右括号的个数判断是否还可以组成…

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] 题意:…

题目 Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ "((()))", "(()())", "(())()", "()(())", "()()()" ]…