拓扑 前缀 线性leetcode
codility 和 leetcode 对比
根据网上的信息，codility 和 leetcode 都是用于评估编程技能的在线平台，它们都提供了不同难度和类型的编程挑战，支持多种编程语言，并可以用于招聘和面试的过程中。 不过，它们也有一些区别，比如： codility 更专注于工程团队的技能评估，它提供了 CodeCheck, CodeLiv ......
leetcode872叶相似树
这道题是考虑的深度优先搜索，使用递归 vecotr和queue入队操作并不相同： vector只能使用push_back(); queue既可以使用push()还可以使用push_back() void FindLeaf(TreeNode* root,vector<int>& v){ if(!roo ......
LeetCode 347. 前 K 个高频元素
# 快排思想 - 注意，这里是倒序排序，因此应该`while(nums[i].cnt>x);` ``` class Solution { public: struct element { int val,cnt; element(int a,int b) { val=a; cnt=b; } }; v ......
LeetCode -- 773. 滑动谜题
启发式搜索 class Solution { struct Node { string str; int x, y; int val; }; int n = 2, m = 3; string e = "123450"; int dx[4] = {-1, 0, 1, 0}; int dy[4] = { ......
acwing3488 常规异或前缀树+更新策略
https://www.acwing.com/problem/content/3488/ 不同于一般的子数组异或和（异或前缀和+前缀树），本题对子数组长度作了限制。 依旧考虑维护一颗前缀树，记录前缀树的每个节点在当前状态是否可达。只是规定树内涉及的节点规模不大于m。 可以发现，我们在[x, x + ......
[LeetCode] 2297. Jump Game VIII
You are given a 0-indexed integer array nums of length n. You are initially standing at index 0. You can jump from index i to index j where i < j if: ......
leetcode 28 459 总结 KMP算法
[toc] #28 ##解法一，暴力法 ``` //暴力 if(haystack.length() pi(m); for (int i = 1, j = 0; i 0 && needle[i] != needle[j]) { j = pi[j - 1]; } if (needle[i] == nee ......
[LeetCode] 2408. Design SQL
You are given n tables represented with two arrays names and columns, where names[i] is the name of the ith table and columns[i] is the number of colu ......
leetcode-1518-easy
Water Bottles ``` There are numBottles water bottles that are initially full of water. You can exchange numExchange empty water bottles from the marke ......
PKUSC2018 最大前缀和
这个期望显然是诈骗，即统计每种排列最大前缀和之和。 对于某个排列 $a$，令 $s(l,r)=\sum\limits_{k=l}^ra_k$。考虑前缀 $[1,i]$ 成为答案的**充要条件**： - $\forall 1i,s(i+1,j)<0$，否则加上这段不劣（钦定取的是**最大并且最靠后** ......
【ElasticSearch】大数据量情况下的前缀、中缀实时搜索方案
大数据、elasticsearch、实时搜索、search_as_you_type、Completion Suggester、查询优化、前缀匹配、中缀匹配 ......
Codility / LeetCode的重要性与注意事项
Codility / Leetcode 不只会针对回答内容给出最终分数，也会一并记录解题的过程供面试官参考; 相较于现场考试，Codility / Leetcode可以省下更多时间，也能让求职者在最熟悉的环境发挥实力。 进行测验前 先查看Codility / Leetcode FAQ，并完成demo ......
学习线性基相关
在线性空间中，线性基是一组线性无关的向量组，且在其所在的向量空间中是一个极大线性无关向量组 我们在算法里，可以看作是若干个数的集合 在一个序列中，取其线性基中的任意几个数，可以得到原来序列的任何一个数 线性基中的数都是唯一的 ## 如何构造线性基 贪心的方法 从高位往低位扫，设a[x]为第x位上是1 ......
线性代数
## 7/19 ### [[ABC189E] Rotate and Flip](https://www.luogu.com.cn/problem/AT_abc189_e) ### 题意： **给定在二维平面上的一些点，给定 $m$ 次操作，为顺时针转 $\frac{\pi}{2} $，逆时针旋转 $ ......
[LeetCode] 2268. Minimum Number of Keypresses
You have a keypad with 9 buttons, numbered from 1 to 9, each mapped to lowercase English letters. You can choose which characters each button is match ......
[LeetCode] 2323. Find Minimum Time to Finish All Jobs II
You are given two 0-indexed integer arrays jobs and workers of equal length, where jobs[i] is the amount of time needed to complete the ith job, and w ......
[LeetCode] 2330. Valid Palindrome IV
You are given a 0-indexed string s consisting of only lowercase English letters. In one operation, you can change any character of s to any other char ......
[LeetCode] 2340. Minimum Adjacent Swaps to Make a Valid Array
You are given a 0-indexed integer array nums. Swaps of adjacent elements are able to be performed on nums. A valid array meets the following condition ......
[LeetCode] 2422. Merge Operations to Turn Array Into a Palindrome
You are given an array nums consisting of positive integers. You can perform the following operation on the array any number of times: Choose any two ......
[LeetCode] 1676. Lowest Common Ancestor of a Binary Tree IV
Given the root of a binary tree and an array of TreeNode objects nodes, return the lowest common ancestor (LCA) of all the nodes in nodes. All the nod ......
LeetCode之0661, 二维向量初始化
img[i][j]周围的单元格，img[i+i1][j+j1], i1=-1,0,1, j1=-1,0,1, 每个都判断一次。O(9*m*n) class Solution { public: std::vector<std::vector<int>> imageSmoother( std::vec ......
Leetcode之0709, 修改字符串
1 class Solution { 2 public: 3 string toLowerCase(string s) { 4 for(char &ch: s){ 5 if(ch>='A' && ch<='Z'){ 6 ch=tolower(ch); 7 } 8 } 9 return s; 10 } ......
[LeetCode] 2486. Append Characters to String to Make Subsequence
You are given two strings s and t consisting of only lowercase English letters. Return the minimum number of characters that need to be appended to th ......
[刷题记录Day4]Leetcode链表专题
# No.1 ## 题目 [两两交换链表中的节点](https://leetcode.cn/problems/swap-nodes-in-pairs/) ## 思路 - 模拟类型题目 - 两个节点前后交换，同时记住原来的下一个节点 - 虚拟头节点 ## 代码 ```Java public ListN ......
LeetCode 1201. Ugly Number III 数学+二分答案
An ugly number is a positive integer that is divisible by $a$, $b$, or $c$. Given four integers $n$, $a$, $b$, and $c$, return the $n$th ugly number. ......
拓扑排序
定义 : 对一个有向图构造拓扑序列，排序类似流程图那样按先干什么后干什么这样排序 拿大学教学安排举个例子（图来自oi wiki）  难度：[简单](#Simple) [中等](#middle) [困难](#hard) 类型：[数组](#数组) [链表](#链表) [字符串](#字符串) [二叉树](#二叉树) [排序](#排序) 解法：[递归和迭代](#递归和迭代) [滑动窗口 ]( ......