make no mistake, we are the last line of defense.…

As we all know, Matt is an outstanding contestant in ACM-ICPC. Graph problems are his favorite.Once, he came up with a simple algorithm for finding the maximal independent set in trees by mistake.A tree is a connected undirected graph without cycles,…

Stock market volatility continues unabated. It may be too early to tell, but I’m marking the top of this current market correction at July 20, with the bottom still to be determined (though I’d say it’s still a few weeks off). Since July 20, investor…

PHP Advanced and Object-Oriented Programming 3rd Edition Related to modularity is abstraction: classes should be defined broadly. This is a common and understandable beginner’s mistake. As an example, instead of designing a class for interacting with…

[common mistake of closure in loops] 下例中item引用的始终是最后一个值. function showHelp(help) { document.getElementById('help').innerHTML = help; } function setupHelp() { var helpText = [ {'id': 'email', 'help': 'Your e-mail address'}, {'id': 'name', 'help': 'You…

One of the top suggestions (currently #15 on uservoice) for improving C# is the addition of non-nullable reference types. This is not surprising, considering the number of functions that start with a block of ‘if (x == null) throw new ArgumentNullExc…

音标复习 绿色:连读:                  红色:略读:               蓝色:浊化:               橙色:弱读 口语蜕变(2017/6/24) If your dream was big enough and you had the guts to follow it, there was truly a fortune to be made. [ɪf] [jʊr] [drim] [wɒz] [bɪɡ] [ɪˈnʌf] [əndˌ ən] [ju] [h…

原文作者: Roman Elizarov 原文地址: Null is your firend, not a mistake 译者:秉心说 Kotlin Island from Wikimedia by Pavlikhin, CC BY-SA 4.0 我使用 Java 语言编程已经很久很久了,掌握了通过 Java 编写和维护大型软件(百万行代码)应该注意些什么,并亲眼目睹了全行业都在竭力避免空指针异常 NullPointerException(NPE),它困扰着大大小小的 Java 类库.在 20…

Just A Mistake Time Limit: 5000/5000 MS (Java/Others)    Memory Limit: 512000/512000 K (Java/Others)Total Submission(s): 168    Accepted Submission(s): 41 Problem Description As we all know, Matt is an outstanding contestant in ACM-ICPC. Graph proble…

又一道pwnable,我还没放弃.. ssh mistake@pwnable.kr -p2222 (pw:guest) 源代码如下: #include <stdio.h> #include <fcntl.h> #define PW_LEN 10 #define XORKEY 1 void xor(char* s, int len){ int i; ; i<len; i++){ s[i] ^= XORKEY; } } int main(int argc, char* argv[…

B. Silly Mistake 题目大意: 首先定义有效的一天: 每一个不同的数字只能进去一次,出来一次,正数代表进去,负数代表出来 每一个人不能过夜 不合理: 一个数字只有进去,或者只有出来则是无效的 给你一个数组,让你把数字分成若干个有效天,不要求最大化这个天数,也不要求最小化这个天数, 问怎么划分,如果无法划分则输出-1 题目思路: 这个题目我觉得不是很简单,反正我写的比较吃力 首先我们要模拟这个进入和出去,则可以用一个bool数组,为真则是进去,为假则是出去. 其次我们要判断是不是同一…

发音相似容易混淆的词汇 alteration  英 [ɔːltə'reɪʃ(ə)n; 'ɒl-]  美 [,ɔltə'reʃən]  n. 修改,改变:变更 alteration /ˌɔːltəˈreɪʃən/  TEM4 1.N-COUNT An alteration is a change in or to something. 改动 例: Making some simple alterations to your diet will make you feel fitter. 对你的饮食…

$ git init Initialized empty Git repository in .git/ $ echo "testing reset" > file1 $ git add file1 $ git commit -m 'added file1' Created initial commit 1a75c1d: added file1 1 files changed, 1 insertions(+), 0 deletions(-) create mode 100644…

git init echo hello >> test.txt git add test.txt Now the blob is created but it is referenced by the index so it will no be listed with git fsck until we reset. So we reset... git reset --hard git fsck you will get a dangling blob ce013625030ba8dba9…

They’ve got a problem with their existing code, which tries to use a closure. Check it out: function assignLaser( shark, sharkList ){ var stationAssignment; for(var i = 0; i<sharkList.length; i++){ if(shark == sharkList[i]){ stationAssignment = funct…

2019-03-29 [NOI2016]网格 如果是矩形,要记得考虑n或m=1的情况,不要潜意识里就以为矩形就是接近正方形的那种理想矩形. 写bool型的函数,return 的语句要想清楚,不要放错位置. 2019-03-30 [NOI2013]矩阵游戏 写高精度如果重载了运算符,数组大小不能开的太大(不要超过1e4比较安全吧) 实在太大就不要用重载了. 矩阵乘法的矩阵要尽量优化,不要随便就写出一个3*3的矩阵,其实只要1*2就够了 O(27)与O(2)的常数差距啊.. 2019-03-31 […

题目:愚蠢的错误 题意:中心公司有一个办公室有一个成熟的安全系统,这里面有10^6个雇员,编号从1到10^6 安全系统有入口和出口,数字i表示第i个雇员进入,-i表示第i个雇员出去 公司有一些严格的规矩: 1.雇员一天可以进入办公司最多一次 2.如果今天雇员没进雇员,他是无法出去的 3.办公室空的,代表里面的人都出去了 [1, 7, -7, 3, -1, -3]表示一个有效的一天,1进入,7进入,7出去,3进入,1出去,3出去 这里有a1,a2,...,an表示它们进出的序列,这个序列表示一天或…

#include<iostream> #include<map> #include<set> #include<algorithm> using namespace std; ; map<int,bool>vis; set<int>b; int n,a[N],c[N]; int main() { scanf("%d",&n); ; i <= n; i++) { scanf("%d"…

题意:有一个公司,每天有员工进出,$a[i]>0$时表示$a[i]$这个员工进入公司,$a[i]<0$时表示$-a[i]$这个员工出公司,公司对进出办公室有一些严格的规定 员工每天最多只能进入一次办公室 如果那天他没有进办公室的话,他显然不能离开 每天开始和结束时,办公室都是空的(员工不能呆在晚上),办公室也可能在一天中的任何时候都是空的 现在给你序列$a$($a[i] \neq 0$),问你是否能够把数组$a$分为几个相邻的子数组,使得每一个子数组员工的进出情况符合要求并输出每一个子数组的长…

I'm using ubuntu14 LTS. Problems: 1. When run roscore, got a mistake and an advice to ping the localhost. 2. Nearly every time I run a directive with sudo, I got a warning that unable to resolve host. It turns out, the reason is I changed the ubuntu…

题目链接:Recover Binary Search Tree | LeetCode OJ 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 constan…

Sept. 13, 2015 Spent more than a few hours to work on the leetcode problem, and my favorite blogs about this problems: 1. http://siddontang.gitbooks.io/leetcode-solution/content/tree/construct_binary_tree.html 2.http://blog.csdn.net/linhuanmars/artic…

Source: Research gate Stafford Michahial EEG is a very low frequency.. and literature will give us the region where Alpha, Beta, Mu, signals are generated in Brain... and to reduce the complexity and to avoid interference as much as possible.. we go…

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? confused what "{1,#,2,3}"…

examples come from native speaker Put john in the loop about this. He will have good advice. Why have I been cut out of the loop? I need to know about this stuff. Who all is 'in the know'? I need to be sure I know so I do not talk to someone out of t…

如何在Texstudio编辑软件内加载"语法检查词典"? How to make dictionary work in TexStudio I am using TexStudio as my LaTex IDE and honestly speaking I find it better than others available for the same purpose. One of the advantages is that you can use dictionary fo…

我 2006 年开始工作,至今已经 10 年.10 年是个里程碑,我开始回顾自己曾经犯过的错误,以及我希望从同行那里得到什么类型的忠告.一切都在快速改变,10 年了,我不能确定这些秘诀是否还有用. 不管您是新人还是老手,您都会发现我的话是有用的.我期待听到您的观点,所以请不吝赐教给我回信. 坚持使用一种平台,框架或者语言 在过去 10 年间我所犯的最大的错误是:每次换工作时我都会换一个软件平台. 开始我使用 Enterprise Java Development,然后是嵌入 C 软件,然后,对于…

http://www.jenkinssoftware.com/raknet/manual/creatingpackets.html Creating Packets with Bitstreams Write less data with bitstreams Lets take our mine example above and use a bitstream to write it out instead. We have all the same data as before.Messa…

使用Flashback Query的场景包括如下: 摘自官档 Recovering lost data or undoing incorrect, committed changes. For example, if you mistakenly delete or update rows, and then commit them, you can immediately undo the mistake. Comparing current data with the correspondi…

获取用户信息,需要获取 access_token.openid 然后调用接口https://api.weixin.qq.com/cgi-bin/user/info?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN access_token:公众号的全局唯一票据, 获取access_token,需要调用https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&a…