算法题丨Next Permutation

描述 Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possible, it must rearrange it as the lowest possible order (ie, sorted in ascending order). The replac…

LeetCode算法题-Letter Case Permutation（Java实现）

这是悦乐书的第315次更新,第336篇原创 01 看题和准备今天介绍的是LeetCode算法题中Easy级别的第184题(顺位题号是784).给定一个字符串S,将每个字母单独转换为小写或大写以创建另一个字符串.返回可以创建的所有可能字符串的数组.例如: 输入:S ="a1b2" 输出:["a1b2","A1b2","a1B2","A1B2"] 输入:S ="3z4" 输出:["…

算法题丨Remove Duplicates from Sorted Array II

描述 Follow up for "Remove Duplicates": What if duplicates are allowed at most twice? 示例 Given sorted array nums = [1,1,1,2,2,3], Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3. It doesn't matte…

算法题丨Longest Consecutive Sequence

描述 Given an unsorted array of integers, find the length of the longest consecutive elements sequence. Your algorithm should run in O(n) complexity. 示例 Given [100, 4, 200, 1, 3, 2], The longest consecutive elements sequence is [1, 2, 3, 4]. Return its…

算法题丨Two Sum

描述 Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. 示例 Given nums = [2, 7, 11, 15], t…

算法题丨3Sum

描述 Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: The solution set must not contain duplicate triplets. 示例 Given array S = [-1, 0, 1, 2…

算法题丨3Sum Closest

描述 Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution. 示例 Given array S = {-1 2 1 -4},…

算法题丨4Sum

描述 Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. Note: The solution set must not contain duplicate quadruplets. 示例 Give…

算法题丨Remove Element

描述 Given an array and a value, remove all instances of that value in-place and return the new length. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. The order of elements…

算法题丨Move Zeroes

描述 Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements. Note: 1.You must do this in-place without making a copy of the array. 2.Minimize the total number of operations.…

算法题丨Remove Duplicates from Sorted Array

描述 Given a sorted array, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. 示…

高盛昂赛算法题先写corner case

[方法] 字写大点,先注释框架链表:指针走就行了,最多是两个同时一起走. 两个链表求交点 //corner case if (headA == null || headB == null) { return null; } //keep the same length int A_len = getLength(headA); int B_len = getLength(headB); while (A_len > B_len) { headA = headA.next; A_len--; }…

一道java算法题分析

最近在面试中遇到这样的一道算法题: 求100!的结果的各位数之和为多少? 如:5!=5*4*3*2*1=120,那么他们的和为1+2+0=3这道题不算难,不过倒是注意的细节也有一些:1.数据的越界问题如果求的是171的阶乘的话,就会超出double类型的存储范围,这时候就要处理了,不然得到的结果是:Infinity1.可以通过java的BigInteger类来进行处理:2.可以将结果中的每一位数存在一个int类型的数组中,不过这个方法还没有想出来代码如下: packa…

FCC上的初级算法题

核心提示:FCC的算法题一共16道.跟之前简单到令人发指的基础题目相比,难度是上了一个台阶.主要涉及初步的字符串,数组等运算.仍然属于基础的基础,官方网站给出的建议完成时间为50小时,超出了之前所有非项目题目的一倍还多.由此可见它的分量.现将自己的解题过程做个记录,有兴趣的人可以一起来试试. 2017.1更新: 博客门可罗雀,阅读数最高的几篇文章竟无一例外全是FCC的答案.聊天室里最多的话题是"我要源码".拿来主义确实很好,但我希望写自己的代码.如果有一两个人能贬低这些代码,提出更好的…

解决一道leetcode算法题的曲折过程及引发的思考

写在前面本题实际解题过程是从 40秒 --> 24秒 -->1.5秒 --> 715ms --> 320ms --> 48ms --> 36ms --> 28ms 最后以28ms的运行速度告结, 有更好的解法或者减少算法复杂度的博友可以给我发消息也可以评论, 我们一起讨论. 第一次在leetcode解算法题,想来个开门红,先挑选一道简单的题目AC了再说.leetcode对每道题都有一个难度提示,分别是easy,medium,hard 于是在第一页中看到了几道标…

js 中的算法题，那些经常看到的

js中遇到的算法题不是很多,可以说基本遇不到.但面试的时候,尤其是一些大公司,总是会出这样那样的算法题,考察一个程序员的逻辑思维能力.如下: 1.回文. 回文是指把相同的词汇或句子,在下文中调换位置或颠倒过来,产生收尾回环的情况,也叫回环.如:mamam,redivider. 实现回文不是我们最常用到的for循环,而是reverse的运用.将字符串转化为数组,将数组顺序颠倒后,再转化为字符串,这个过程就实现的回文. 代码的实现: function back(str){ return str==…

JavaScript算法题之–随机数的生成

JavaScript算法题之–随机数的生成需求描述:从一组有序的数据中生成一组随机并且不重复的数,类似于简单的抽奖程序的实现. 先来生成一个有序的数组: 1 var arr = [], 2 length = 100, 3 i = 0; 4 5 for( ; i < length; i++ ){ 6 arr.push( i ); 7 } 从一个长度为 100 的有序数组中随机拿出 10 个随机的数,并且不能有重复. 方法1:随机抽取法 01 var gRandomAr…

简单的算法题， Find Minimum in Rotated Sorted Array 的Python实现。

简单的算法题, Find Minimum in Rotated Sorted Array 的Python实现. 题目: Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. You may assume no duplicate exists in t…