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1, Title: Given a string, the output of all dictionary order.Such as:Input string: ' AC ', Output: [' AC ', ' CA ']Input string: ' abc ', Output: [' abc ', ' ACB ', ' bac ', ' BCA ', ' cab ', ' CBA ']Input string: ' ACC ', output: [' acc ', ' CAC ', ' CCA ']2. Recursion:such as: ' abc ', for ' a ', return ' BC ' of the full permutation dictionary order, for ' B ', return ' AC ' of the full array, for ' C ', return ' AB ' the full array. "Loop plus recursion"Code Listing 1:defPrintstr (s): Listst

elements by combining labels with attributesIv. CSS: Hierarchical relationships1. In the previous XPath, we talked about hierarchical relationship positioning, where CSS can achieve the same effect2. xpath://form[@id = ' form ']/span/input andform[@class = ' FM ']/span/input can also be implemented with CSSFive, CSS: index1. As an example, follow the previous article2.css can also be indexed option:nth-child (1) to locate the child elements, which is very different from the XPath notation, in f

In front we pave a lot of details, is to let everyone more clear prototype use details;Now you can combine the previous knowledge and write a function to quickly build an inheritance relationship based on the prototype chain:function extend (child, Parent) {var F = function () {}; F.prototype = Parent.prototype; Child.prototype = new F (); Child.prototype.constructor = child; Child.uber = Parent.prototype;}It is also very easy to use:function Shape () {}//augment prototypeShape.prototype.name =

adept at handling repetitive tasks. It is easy to traverse a long list with a while or for loop.Responding to EventsCSS provides: pseudo-class attributes such as hover allow us to change the style based on the state of the HTML element. The DOM can also respond to changes in the state of an HTML element through events such as onmouseover. So when to use: hover, when to use onmouseover?The simplest answer is to choose the easiest way to achieve it. For example, if you just want the link to chang

Python3 Set Set set concept of setsThe collection is a mutable containerData objects in the collection are in default (cannot be repeated multiple times)A collection is an unordered storage structure, and the data in the collection has no precedence relationshipA collection is a dictionary that is equivalent to a key and has no value, then the key is the collection's data,The elements within the collection must be immutable objectsThe collection is iterative (can be traversed with for and so on)

four attribute range constants, as follows: request as an exampleExample: pagescopedemo04.jsp1 pagescopedemo05.jsp1 Operation Result:　　From the running result you can see that the property scope set by the PageContext object call SetAttribute () method in pagescopedemo04.jsp is the property scope of the request, so when this method is called, The scope constant request_scope of an int type is passed in, and the function of this Request_scope property scope constant is to tell the PageContext o

on the list can use sshd to build the shellDenyusers Westos # #用户黑名单650) this.width=650; "Src=" https://s4.51cto.com/wyfs02/M02/8F/C3/wKioL1jsbIPzGGz5AABfkOMC-kg713.png-wh_500x0-wm_ 3-wmp_4-s_3076357921.png "style=" Float:none; "title=" screenshot from 2017-04-09 21-34-53.png "alt=" Wkiol1jsbipzggz5aabfkomc-kg713.png-wh_50 "/>650) this.width=650; "Src=" https://s4.51cto.com/wyfs02/M00/8F/C4/wKiom1jsbIWg7sMDAAFKJY-eJts919.png-wh_500x0-wm_ 3-wmp_4-s_2315790415.png "style=" Float:none; "title=" sc

configuration file/etc/ssh/sshd_configpasswordauthentication Yes|no # #是否开启用户密码认证, yes to support no for offPermitrootlogin Yes|no # #是否允许超级用户登陆allowusers Student Westos # #用户白名单, only users who appear on the list can use sshd to build the shelldenyusers Westos # #用户黑名单650) this.width=650; "src=" https://s3.51cto.com/wyfs02/M01/8F/CA/wKioL1jsp6aQMvmoAACTBhiQqPo501.jpg "style=" float : none; "title=" 36020170411175254242.jpg "alt=" Wkiol1jsp6aqmvmoaactbhiqqpo501.jpg "/>650) this.width=650; "src=

determines whether they store numbers or strings. In general, an array in awk is used to collect information from records, which can be used to calculate sums, count words, and how many times the tracking template is matched.Show/ETC/PASSWD's account650) this.width=650; "alt=" Copy Code "src="/img/fz.gif "/>Awk-f ': ' BEGIN {count=0;}{Name[count] = $1;count++;}; End{for (i = 0; i 650) this.width=650; "alt=" Copy Code "src="/img/fz.gif "/>This uses the For loop to iterate through the arrayThis a

_pid_file_path"'off (kill-0$mysqld _pid2>/dev/null) ThenEcho $echo _n " shutting down MySQL "Kill $mysqld _pid# mysqld Shouldremove The PID file when it exits, so wait for it.Wait_for_pid removed "$mysqld _pid" "$mysqld _pid_file_path" ; Return_value=$?ElseLog_failure_msg "MySQL Server process #$mysqld _pidis notrunning! "RM " $mysqld _pid_file_path "fi# Delete Lock Forredhat/suseif test - F " $lock _file_path " ThenRM - F " $lock _file_path "fiExit $return _valueElseLog_failure_msg "mysqlserve

1. Create user[Email protected]/]# useradd-g root Elasticsearch[Email protected]/]# passwd Elasticsearch2. Unzip the package to the specified directory[Email protected] ~]$ TAR-ZXF elasticsearch-5.2.2.tar.gz[Email protected] ~]$ MV Elasticsearch-5.2.2/opt/modules[Email protected] ~]$ Ls/opt/modules3. Modify Permissions[Email protected] modules]# chmod 755-r elasticsearch-5.2.2/[Email protected] modules]# chmod 755-r hadoop-2.6.0/[Email protected] modules]# chmod 755-r jdk1.7.0_80/4. Modify the O

Display and switching of directoriesDirectory content display command: LSCurrent directory Switch command: CDCurrent directory display commands: PWDAdditions and copies of catalogsDirectory new command: mkdirDirectory Copy command: CPDeletion of directoriesEmpty directory Delete command: rmdirNon-empty directory Delete command: RM-RFMoving and renaming of directoriesDirectory move renaming command: MVNetEase Cloud Classroom _linux Operating system introduction (embedded development 0 Basic Ⅰ) _

efficient algorithm this doesn ' t need to go back and forth between the X's and the Thetas, but that can solve for th ETA and X simultaneously}Collaborative Filteringoptimization ObjectiveNote:1. Sum over J says, for every user, the sum of all the movies rated by, user.for every movie I,sum over a ll the users J that has rated that movie.2. Just something over all the user movie pairs for which has a rating.3. If you were to hold the X's constant and just minimize with respect to the thetas th

virtualbox-4.3_4.3. the-98988~ubuntu~raring_amd64.deb...Unpacking virtualbox-4.3(4.3. the-98988~ubuntu~raring)...Setting up virtualbox-4.3(4.3. the-98988~ubuntu~raring)...Adding group ' vboxusers ' (GID 127) ... Done.3. View Deb's information-I parameter, view details$ dpkg-i virtualbox-4.3_4. 3. the-98988~ubuntu~raring_amd64.debNewDebian package,version 2.0. Size64750912 bytes: Control archive=23332 bytes.118 bytes,4 LinesConffiles1371 bytes, - LinesControl58951 bytes,641 LinesMd5sums14579 byt

(E element)//place the element to the the queue, but only return faulse instead of throw an Exceptione poll// Removes element at head of the "queue", in case of failure return null instead of throwing Exceptione peek ()//return head WI Thout removingJava 7 added Dequeue, which means can operate from 2 ends of the the queue, (head or tial). Corresponding method changed As:offerlast ();p ollfirst ();p olllast ();p eelfirst ();p eeklast ();-blockingqueueEnhance The capablity of timed wait, so this

(); } } Public Static voidMain (String []args) {NewTestsocket (); } PublicSocket Getsock () {returnsock; } Public voidSetsock (Socket sock) { This. Sock =sock; } PublicServerSocket getserver () {returnserver; } Public voidsetserver (serversocket server) { This. Server =server; } PublicString getString (InputStream in)throwsioexception{String str=""; byte[] b=New byte[1024]; intLen=-1; while(len = In.read (b))!=-1) {System.out.println (

condition after the assert is "value ?? Throws an exception when the assertion condition is not met, by default, shows only where the exception was thrown, and does not show what throws the exception, so for the exception information to be more explicit, you can specify an exception description for the Assert statement.>>> value = 20>>> assert value This example demonstrates the use of assertions.name = "Bill" # 定义变量nameassert name == "Bill" # 断言条件表

(4) Classes and classes, classes and interfaces, interfaces and interfacesA: Class and class inheritance relationship, can only single inheritance, multi-layer inheritance B: class and interface implementation relationship, can be single implementation, can also be implemented. Can also inherit a class at the same time, implement multiple interfaces C: interface and interface inheritance, can be single-inheritance, can also inherit (5) abstract class and interface differences (self-completion)?

array int[] B =New int[Length];//construct B Array//count the number of elements in a, and deposit in the C array for(inti = 0; i ) {C[array[i]]+ = 1; } //accumulate the number of each element: Set the value of the C array for(inti = 0; I ) {sum+=C[i]; C[i]=sum; } //iterate a array, construct B array for(inti = length-1; I >= 0; i--) {B[c[array[i]]-1] = array[i];//Place the element in a in the position specified in array b after sortingC[array[i]]--;//this element in C-1 is

possible locations, and then put it into the stack, random, directly find a location, and then directly randomly from the one to find it. The method of array simulation is mainly to avoid the low efficiency of vectors and to realize the simplicity of the stack. And the extension is more convenient, if you want to random and more, the modification is also very convenient.BOOL Randomnew () {intempty_block[ -][2];int sum=0; for(inti =0; I 4; ++i) { for(intj =0; J 4; ++J) {if(Data[i][j] = =0) {empt