Rosetta Code/Tasks without examples

Rosetta Code/Tasks without examples is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

A RosettaCode contributor is going on a long journey. To ease the boredom of a long flight he takes his favourite programming language manual and a list of RosettaCode tasks, but there's a catch: the tasks have to be description only and not include all the solutions already supplied by other programmers.

Task: Scrape http://rosettacode.org/wiki/Category:Programming_Tasks for all the tasks. Traverse the links. Extract the text or html between a tag with a class of "infobox" and the beginning of the table with the id of "toc".

Perl 6

Works with: Rakudo version 2017.10

<lang perl6>use HTTP::UserAgent; use Gumbo;

my $ua = HTTP::UserAgent.new; my $taskfile = './RC_tasks.html';

1. Get list of Tasks

say "Updating Programming_Tasks list..."; my $page = "http://rosettacode.org/wiki/Category:Programming_Tasks"; my $html = $ua.get($page).content;

my $xmldoc = parse-html($html, :TAG

, :id<mw-pages>); my @tasks = parse-html($xmldoc[0].Str, :TAG

).Str.comb( /'/wiki/' <-["]>+ / )».substr(6); #" my $f = open("./RC_Programming_Tasks.txt", :w) or die "$!\n"; note "Writing Programming_Tasks file..."; $f.print( @tasks.join("\n") ); $f.close; sleep .5; for 'Programming_Tasks' -> $category { # Scrape info from each page. note "Loading $category file..."; note "Retreiving tasks..."; my @entries = "./RC_{$category}.txt".IO.slurp.lines; for @entries -> $title { note $title; # Get the raw page my $html = $ua.get: "http://rosettacode.org/wiki/{$title}"; # Filter out the actual task description $html.content ~~ m|'

<div' .+? 'using any language you may know.

' (.+?) '<div id="toc"'|;

       my $task = cleanup $0.Str;

       # save to a file
       my $fh = $taskfile.IO.open :a;

$fh.put: "

---

\n $title\n

---

\n$task";

       $fh.close;

       sleep 3; # Don't pound the server
   }

}

sub cleanup ( $string ) {

$string.subst( /^.+ '

'/, )

}</lang>

Abridged sample output:

---

    100_doors

---

There are 100 doors in a row that are all initially closed.

You make 100 <a href="/wiki/Rosetta_Code:Multiple_passes" title="Rosetta Code:Multiple passes">passes</a> by the doors.

The first time through, visit every door and  toggle  the door  (if the door is closed,  open it;   if it is open,  close it).

The second time, only visit every 2^nd door   (door #2, #4, #6, ...),   and toggle it.

The third time, visit every 3^rd door   (door #3, #6, #9, ...), etc,   until you only visit the 100^th door.

Task

Answer the question:   what state are the doors in after the last pass?   Which are open, which are closed?

<a href="/wiki/Rosetta_Code:Extra_credit" title="Rosetta Code:Extra credit">Alternate</a>: As noted in this page's   <a href="/wiki/Talk:100_doors" title="Talk:100 doors">discussion page</a>,   the only doors that remain open are those whose numbers are perfect squares.

Opening only those doors is an   <a href="/wiki/Rosetta_Code:Optimization" title="Rosetta Code:Optimization">optimization</a>   that may also be expressed;

however, as should be obvious, this defeats the intent of comparing implementations across programming languages.

---

    15_Puzzle_Game

---

Task

Implement the <a href="http://en.wikipedia.org/wiki/15_puzzle" class="extiw" title="wp:15 puzzle">Fifteen Puzzle Game</a>.

Related Task

• <a href="/wiki/15_puzzle_solver" title="15 puzzle solver">15 Puzzle Solver</a>

---

    15_puzzle_solver

---

Your task is to write a program that finds a solution in the fewest single moves (no multimoves) possible to a random <a href="http://en.wikipedia.org/wiki/15_puzzle" class="extiw" title="wp:15 puzzle">Fifteen Puzzle Game</a>.
For this task you will be using the following puzzle:

15 14  1  6
 9 11  4 12
 0 10  7  3
13  8  5  2

Solution:

 1  2  3  4
 5  6  7  8
 9 10 11 12
13 14 15  0

The output must show the moves' directions, like so: left, left, left, down, right... and so on.
There are 2 solutions with 52 moves:
rrrulddluuuldrurdddrullulurrrddldluurddlulurruldrdrd
rrruldluuldrurdddluulurrrdlddruldluurddlulurruldrrdd
finding either one, or both is an acceptable result.
see: <a rel="nofollow" class="external text" href="http://www.rosettacode.org/wiki/15_puzzle_solver/Optimal_solution">Pretty Print of Optimal Solution</a>

Extra credit.

Solve the following problem:

  0 12  9 13
 15 11 10 14
  3  7  2  5
  4  8  6  1

Related Task

• <a href="/wiki/15_Puzzle_Game" title="15 Puzzle Game">15 puzzle game</a>

...and so on...

VBScript

Uses Internet Explorer (v9 and above) to traverse the DOM in the list page and subsequent task pages. Echoes title and href to the console. Outputs files containing html.

Could output text by retrieving innerText instead of innerHTML in Slurp(). <lang vbscript>Option Explicit

Dim oIE : Set oIE = CreateObject("InternetExplorer.Application")

Dim oFSO : Set oFSO = CreateObject("Scripting.FileSystemObject")

Dim oRE : Set oRE = New RegExp oRE.Pattern = "class=[" & Chr(34) & "'](.*?)[" & Chr(34) & "']" oRE.IgnoreCase = True

oIE.Navigate "http://rosettacode.org/wiki/Category:Programming_Tasks" While oIE.Busy WScript.Sleep 100 Wend

Dim oDoc : Set oDoc = oIE.Document Dim oDict : Set oDict = CreateObject("Scripting.Dictionary")

' build a dictionary of anchors Dim oAnchor Dim oAnchors : Set oAnchors = oDoc.getElementById("mw-pages").getElementsByTagName("a") For Each oAnchor In oAnchors oDict.Add oAnchor.innerText, oAnchor.href Next

'traverse the dictionary of anchors Dim aKeys : aKeys = oDict.Keys() Dim aKey For Each aKey In aKeys Slurp aKey, oDict(aKey) Next

oIE.Quit

Function Slurp(sTitle, sHref) WScript.Echo sTitle, sHref

oIE.Navigate sHref While oIE.Busy WScript.Sleep 100 Wend

Dim oDoc : Set oDoc = oIE.Document

Dim oStart : Set oStart = oDoc.getElementsByClassName("infobox")(0) Dim oCursor : Set oCursor = oStart Dim sDescription : sDescription = vbNullString Dim oThere Dim iErr

Do While oCursor.tagName <> "TABLE" And oCursor.id <> "toc" Set oThere = oCursor sDescription = sDescription & oThere.innerHTML & vbNewLine On Error Resume Next Set oCursor = oCursor.nextElementSibling iErr = Err.Number On Error Goto 0 If iErr <> 0 Then Exit Do End If Loop

dim sTitle2 sTitle2 = Replace(sTitle,"/","_") sTitle2 = Replace(sTitle2,Chr(34),"'") sTitle2 = Replace(sTitle2,"*",".")

Dim oHandle : Set oHandle = oFSO.CreateTextFile(sTitle2 & ".htm", True, True) oHandle.Write "<a href='" & sHref & "'>" & sTitle & "</a>

" oHandle.Write sDescription oHandle.Close

oIE.Stop

End Function </lang>

zkl

This is a bit of a twist on the task: Programmer wants to know which tasks have not been implimeted by their favorite language.

Uses libraries cURL and YAJL (yet another json library). <lang zkl>var [const] CURL=Import("zklCurl"), YAJL=Import("zklYAJL")[0];

fcn getTasks(language){

  continueValue,tasks,curl := "",Data(0,String), CURL();  // "nm\0nm\0...."
  do{	// eg 5 times
     page:=curl.get(("http://rosettacode.org/mw/api.php?"
        "action=query&cmlimit=500"

"&format=json" "&list=categorymembers" "&cmtitle=Category:%s" "&cmcontinue=%s").fmt(language,continueValue),Void);

     page=page[0];  // get HTML body
     json:=YAJL().write(page).close();
     json["query"]["categorymembers"].pump(tasks,T("get","title"));
     continueValue=json.find("continue") #{continue : -||,cmcontinue:page|954|19)}
         .toList()	# ( ("continue","-||"), ("cmcontinue","page|954|19") )

.apply("concat","=").concat("&"); # continue=-||&cmcontinue=page|954|19

  }while(continueValue);
  tasks

}

var allTasks =getTasks.future("Programming_Tasks"); // thread var draftTasks=getTasks.future("Draft_Programming_Tasks"); // thread var tasks =getTasks.future(lang); // thread

fcn newTasks{

  langTasks:=tasks.pump(Dictionary().add.fp1(Void)); // { "Semordnilap":Void }
  unimplementedTasks:=allTasks.filter('!(langTasks.holds))
            .extend(draftTasks.filter('!(langTasks.holds)));

1. if 0

  unimplementedTasks.pump(List()).sort().pump(Console.println);

1. else // this next part is very very slow, useless, can't find a wikimedia api

      // and the amount of information is pretty overwhelming
  curl:=CURL();
  foreach task in (unimplementedTasks.pump(List()).sort()){
     // some task names have a / in them, can't url encode: "Active Directory/Connect"
     page:="https://rosettacode.org/wiki/" + task.replace(" ","_");
     page:=curl.get(page)[0];  // sloooow

s,s := page.find("\"infobox\""), page.find("

",s); if(not (e:=page.find("<div id=\"toc\"",s))) e:=page.find("

",s); println("

%s

\n%s\n

---

".fmt(task,page[s,e-s].text));

  }

1. endif

}

newTasks();</lang>

Concise Output:

$ zkl rs_tasks_without.zkl 
15 Puzzle Game
15 puzzle solver
2048
ASCII art diagram converter
AVL tree
Ackermann function
...

Verbose Output:

15 Puzzle Game

Implement the <a href="http://en.wikipedia.org/wiki/15_puzzle" class="extiw" title="wp:15 puzzle">Fifteen Puzzle Game</a>.

Related Task

• <a href="/wiki/15_puzzle_solver" title="15 puzzle solver">15 Puzzle Solver</a>

---

15 puzzle solver

Your task is to write a program that finds a solution in the fewest moves possible single moves to a random <a href="http://en.wikipedia.org/wiki/15_puzzle" class="extiw" title="wp:15 puzzle">Fifteen Puzzle Game</a>.
For this task you will be using the following puzzle:

15 14 1 6

9 11  4 12
0 10  7  3

13 8 5 2

Solution:

1  2  3  4
5  6  7  8
9 10 11 12

13 14 15 0

The output must show the moves' directions, like so: left, left, left, down, right... and so on.
There are 2 solutions with 52 moves:
rrrulddluuuldrurdddrullulurrrddldluurddlulurruldrdrd
rrruldluuldrurdddluulurrrdlddruldluurddlulurruldrrdd
finding either one, or both is an acceptable result.
see: <a rel="nofollow" class="external text" href="http://www.rosettacode.org/wiki/15_puzzle_solver/Optimal_solution">Pretty Print of Optimal Solution</a>

Extra credit.

Solve the following problem:

 0 12  9 13
15 11 10 14
 3  7  2  5
 4  8  6  1

Related Task

• <a href="/wiki/15_Puzzle_Game" title="15 Puzzle Game">15 puzzle game</a>
• <a href="/wiki/A*_search_algorithm" title="A* search algorithm">A* search algorithm</a>

---

2048

The rules are that on each turn the player must choose a direction (up, down, left or right) and all tiles move as far as possible in that direction, some more than others. Two adjacent tiles (in that direction only) with matching numbers combine into one bearing the sum of those numbers. A move is valid when at least one tile can be moved, if only by combination. A new tile with the value of 2 is spawned at the end of each turn at a randomly chosen empty square, if there is one. To win the player must create a tile with the number 2048. The player lo ses if no valid moves are possible.

The name comes from the popular open-source implementation of this game mechanic, <a rel="nofollow" class="external text" href="https://gabrielecirulli.github.io/2048/">2048</a>.

Requirements:

and so on