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  • finding shortest valid path in a colored-edge graphs

    - by user1067083
    Given a directed graph G, with edges colored either green or purple, and a vertex S in G, I must find an algorithm that finds the shortest path from s to each vertex in G so the path includes at most two purple edges (and green as much as needed). I thought of BFS on G after removing all the purple edges, and for every vertex that the shortest path is still infinity, do something to try to find it, but I'm kinda stuck, and it takes alot of the running time as well... Any other suggestions? Thanks in advance

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  • What's a good entity hierarchy for a 2D game?

    - by futlib
    I'm in the process of building a new 2D game out of some code I wrote a while ago. The object hierarchy for entities is like this: Scene (e.g. MainMenu): Contains multiple entities and delegates update()/draw() to each Entity: Base class for all things in a scene (e.g. MenuItem or Alien) Sprite: Base class for all entities that just draw a texture, i.e. don't have their own drawing logic Does it make sense to split up entities and sprites up like that? I think in a 2D game, the terms entity and sprite are somewhat synonymous, right? But I do believe that I need some base class for entities that just draw a texture, as opposed to drawing themselves, to avoid duplication. Most entities are like that. One weird case is my Text class: It derives from Sprite, which accepts either the path of an image or an already loaded texture in its constructor. Text loads a texture in its constructor and passes that to Sprite. Can you outline a design that makes more sense? Or point me to a good object-oriented reference code base for a 2D game? I could only find 3D engine code bases of decent code quality, e.g. Doom 3 and HPL1Engine.

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  • Am I right about the differences between Floyd-Warshall, Dijkstra's and Bellman-Ford algorithms?

    - by Programming Noob
    I've been studying the three and I'm stating my inferences from them below. Could someone tell me if I have understood them accurately enough or not? Thank you. Dijkstra's algorithm is used only when you have a single source and you want to know the smallest path from one node to another, but fails in cases like this Floyd-Warshall's algorithm is used when any of all the nodes can be a source, so you want the shortest distance to reach any destination node from any source node. This only fails when there are negative cycles (this is the most important one. I mean, this is the one I'm least sure about:) 3.Bellman-Ford is used like Dijkstra's, when there is only one source. This can handle negative weights and its working is the same as Floyd-Warshall's except for one source, right? If you need to have a look, the corresponding algorithms are (courtesy Wikipedia): Bellman-Ford: procedure BellmanFord(list vertices, list edges, vertex source) // This implementation takes in a graph, represented as lists of vertices // and edges, and modifies the vertices so that their distance and // predecessor attributes store the shortest paths. // Step 1: initialize graph for each vertex v in vertices: if v is source then v.distance := 0 else v.distance := infinity v.predecessor := null // Step 2: relax edges repeatedly for i from 1 to size(vertices)-1: for each edge uv in edges: // uv is the edge from u to v u := uv.source v := uv.destination if u.distance + uv.weight < v.distance: v.distance := u.distance + uv.weight v.predecessor := u // Step 3: check for negative-weight cycles for each edge uv in edges: u := uv.source v := uv.destination if u.distance + uv.weight < v.distance: error "Graph contains a negative-weight cycle" Dijkstra: 1 function Dijkstra(Graph, source): 2 for each vertex v in Graph: // Initializations 3 dist[v] := infinity ; // Unknown distance function from 4 // source to v 5 previous[v] := undefined ; // Previous node in optimal path 6 // from source 7 8 dist[source] := 0 ; // Distance from source to source 9 Q := the set of all nodes in Graph ; // All nodes in the graph are 10 // unoptimized - thus are in Q 11 while Q is not empty: // The main loop 12 u := vertex in Q with smallest distance in dist[] ; // Start node in first case 13 if dist[u] = infinity: 14 break ; // all remaining vertices are 15 // inaccessible from source 16 17 remove u from Q ; 18 for each neighbor v of u: // where v has not yet been 19 removed from Q. 20 alt := dist[u] + dist_between(u, v) ; 21 if alt < dist[v]: // Relax (u,v,a) 22 dist[v] := alt ; 23 previous[v] := u ; 24 decrease-key v in Q; // Reorder v in the Queue 25 return dist; Floyd-Warshall: 1 /* Assume a function edgeCost(i,j) which returns the cost of the edge from i to j 2 (infinity if there is none). 3 Also assume that n is the number of vertices and edgeCost(i,i) = 0 4 */ 5 6 int path[][]; 7 /* A 2-dimensional matrix. At each step in the algorithm, path[i][j] is the shortest path 8 from i to j using intermediate vertices (1..k-1). Each path[i][j] is initialized to 9 edgeCost(i,j). 10 */ 11 12 procedure FloydWarshall () 13 for k := 1 to n 14 for i := 1 to n 15 for j := 1 to n 16 path[i][j] = min ( path[i][j], path[i][k]+path[k][j] );

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  • What are graphs in laymen's terms

    - by Justin984
    What are graphs, in computer science, and what are they used for? In laymen's terms preferably. I have read the definition on Wikipedia: In computer science, a graph is an abstract data type that is meant to implement the graph and hypergraph concepts from mathematics. A graph data structure consists of a finite (and possibly mutable) set of ordered pairs, called edges or arcs, of certain entities called nodes or vertices. As in mathematics, an edge (x,y) is said to point or go from x to y. The nodes may be part of the graph structure, or may be external entities represented by integer indices or references. but I'm looking for a less formal, easier to understand definition.

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  • Designing binary operations(AND, OR, NOT) in graphs DB's like neo4j

    - by Nicholas
    I'm trying to create a recipe website using a graph database, specifically neo4j using spring-data-neo4j, to try and see what can be done in Graph Databases. My model so far is: (Chef)-[HAS_INGREDIENT]->(Ingredient) (Chef)-[HAS_VALUE]->(Value) (Ingredient)-[HAS_INGREDIENT_VALUE]->(Value) (Recipe)-[REQUIRES_INGREDIENT]->(Ingredient) (Recipe)-[REQUIRES_VALUE]->(Value) I have this set up so I can do things like have the "chef" enter ingredients they have on hand, and suggest recipes, as well as suggest recipes that are close matches, but missing one ingredient. Some recipes can get complex, utilizing AND, OR, and NOT type logic, something like (Milk AND (Butter OR spread OR (vegetable oil OR olive oil))) and I'm wondering if it would be sane to model this in a graph using a tree type representation? An example of what I was thinking is to create three "node" types of AND, OR, and NOT and have each of them connect to the nodes value underneath. How else might this be represented in a Graph Database or is my example above a decent representation?

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  • Qt Graphics Scene mouse event propagation

    - by Olorin
    hello i'm learning qt and i'm doing the folowing to add some widgets to a graphics scene void MainWindow::addWidgets(QList<QWidget *> &list, int code) { if(code == CODE_INFO) { QWidget *layoutWidget = new QWidget(); QVBoxLayout *layout = new QVBoxLayout(); foreach(QWidget *w, list) { layout->addWidget(w); this->connect(((ProductInfo*)w), SIGNAL(productClicked()), this, SLOT(getProductDetails())); } layoutWidget->setLayout(layout); this->scene->addWidget(layoutWidget); } } my ProductInfo class processes mouse release and emits a signal void ProductInfo::mouseReleaseEvent(QMouseEvent *e) { QWidget::mouseReleaseEvent(e); emit productClicked(); } the problem is after adding the widgets to the scene they no longer get the mouse release event and don't emit productClicked signal but if i add them to the main window(not to the scene) they work as expected. What am i doing wrong?

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  • Drawing Directed Acyclic Graphs: Minimizing edge crossing?

    - by Robert Fraser
    Laying out the verticies in a DAG in a tree form (i.e. verticies with no in-edges on top, verticies dependent only on those on the next level, etc.) is rather simple without graph drawing algorithms such as Efficient Sugimiya. However, is there a simple algorithm to do this that minimizes edge crossing? (For some graphs, it may be impossible to completely eliminate edge crossing.) A picture says a thousand words, so is there an algorithm that would suggest: instead of: EDIT: As the picture suggests, a vertex's inputs are always on top and outputs are always below, which is another barrier to just pasting in an existing layout algorithm.

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  • Creating dynamic plots

    - by geoff92
    I'm completely new to web programming but I do have a programming background. I'd like to create a site that allows users to visit, enter some specifications into a form, submit the form, and then receive a graph. I have a few questions about this, only because I'm pretty ignorant: Is there a good framework I should start in? I know a lot of java, I'm okay with python, and I learned Ruby in the past. I figure I might use ruby on rails only because I hear of it so often and I think I've also heard it's easy. If anyone has some other recommendation, please suggest. The user will be entering data into a form. I'm guessing the request they'll be making should be one of a GET request, right? Because I don't intend for any of the data they're entering to modify my server (in fact, I don't intend on having a database). The data the user inputs will be used to perform calculations involving lots of matrices. I've written this functionality in python. If I use ruby on rails, should it be instead written in Ruby? Somewhere I've heard that you can either place the load of the work on your server or on the client's computer. Since the code performs heavy math, which option is preferable? How do I alter the setup to either make the client do the work or my server? Should I be using a "cgi-bin"? In the code that I have now, I use matplotlib, a python library, and then "show" the plot in order to see the graph. I specify the x and y limits, but I am able to "drag" the graph in order to see more data within the plot window. Ultimately, I want a graph to be shown on my site with the drag functionality. Is this possible? What if the client drags the graph so far, more computations must be made? Thanks!

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  • How to display a graph only for business hours with CACTI?

    - by Blast Raider
    I have noticed that I can only display an uninterrupted period with Cacti. I am wondering whether is possible or not to make a custom graph which displaying only the business hours during a period (a week, a month, etc.). If it is possible, how could I configure it on Cacti ? For example, I would like to be able to display a graph with an average inbound/outbound traffic between 8am and 7pm for 5 business days a week of the last month. I would apreciate any help. Thank you.

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  • How can I prepare a cake graph in excel with a result based on 100%?

    - by Pitto
    Hello my friends... I need to distribute correctly a little data in an excel graph. I have the total I've earned last year which should represent the 100% of the cake. Then I have my insurance expenses and I want to understand, graphically, how much of my total income went away to pay insurance... I know that a basic proportion like: total expenses : total insurance costs = 100 : x do the correct math but I can't find a way to display this in a cake graph... Any hints?

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  • How to Draw Lines on the Screen

    - by Geertjan
    I've seen occasional questions on mailing lists about how to use the NetBeans Visual Library to draw lines, e.g., to make graphs or diagrams of various kinds by drawing on the screen. So, rather than drag/drop causing widgets to be added, you'd want widgets to be added on mouse clicks, and you'd want to be able to connect those widgets together somehow. Via the code below, you'll be able to click on the screen, which causes a dot to appear. When you have multiple dots, you can hold down the Ctrl key and connect them together. A guiding line appears to help you position the dots exactly in line with each other. When you go to File | Print, you'll be able to preview and print the diagram you've created. A picture that speaks 1000 words: Here's the code: public final class PlotterTopComponent extends TopComponent { private final Scene scene; private final LayerWidget baseLayer; private final LayerWidget connectionLayer; private final LayerWidget interactionLayer; public PlotterTopComponent() { initComponents(); setName(Bundle.CTL_PlotterTopComponent()); setToolTipText(Bundle.HINT_PlotterTopComponent()); setLayout(new BorderLayout()); this.scene = new Scene(); this.baseLayer = new LayerWidget(scene); this.interactionLayer = new LayerWidget(scene); this.connectionLayer = new LayerWidget(scene); scene.getActions().addAction(new SceneCreateAction()); scene.addChild(baseLayer); scene.addChild(interactionLayer); scene.addChild(connectionLayer); add(scene.createView(), BorderLayout.CENTER); putClientProperty("print.printable", true); } private class SceneCreateAction extends WidgetAction.Adapter { @Override public WidgetAction.State mousePressed(Widget widget, WidgetAction.WidgetMouseEvent event) { if (event.getClickCount() == 1) { if (event.getButton() == MouseEvent.BUTTON1 || event.getButton() == MouseEvent.BUTTON2) { baseLayer.addChild(new BlackDotWidget(scene, widget, event)); repaint(); return WidgetAction.State.CONSUMED; } } return WidgetAction.State.REJECTED; } } private class BlackDotWidget extends ImageWidget { public BlackDotWidget(Scene scene, Widget widget, WidgetAction.WidgetMouseEvent event) { super(scene); setImage(ImageUtilities.loadImage("org/netbeans/plotter/blackdot.gif")); setPreferredLocation(widget.convertLocalToScene(event.getPoint())); getActions().addAction( ActionFactory.createExtendedConnectAction( connectionLayer, new BlackDotConnectProvider())); getActions().addAction( ActionFactory.createAlignWithMoveAction( baseLayer, interactionLayer, ActionFactory.createDefaultAlignWithMoveDecorator())); } } private class BlackDotConnectProvider implements ConnectProvider { @Override public boolean isSourceWidget(Widget source) { return source instanceof BlackDotWidget && source != null ? true : false; } @Override public ConnectorState isTargetWidget(Widget src, Widget trg) { return src != trg && trg instanceof BlackDotWidget ? ConnectorState.ACCEPT : ConnectorState.REJECT; } @Override public boolean hasCustomTargetWidgetResolver(Scene arg0) { return false; } @Override public Widget resolveTargetWidget(Scene arg0, Point arg1) { return null; } @Override public void createConnection(Widget source, Widget target) { ConnectionWidget conn = new ConnectionWidget(scene); conn.setTargetAnchor(AnchorFactory.createCircularAnchor(target, 10)); conn.setSourceAnchor(AnchorFactory.createCircularAnchor(source, 10)); connectionLayer.addChild(conn); } } ... ... ... Note: The code above was written based on the Visual Library tutorials on the NetBeans Platform Learning Trail, in particular via the "ConnectScene" sample in the "test.connect" package, which is part of the very long list of Visual Library samples referred to in the Visual Library tutorials on the NetBeans Platform Learning Trail. The next steps are to add a reconnect action and an action to delete a dot by double-clicking on it. Would be interesting to change the connecting line so that the length of the line were to be shown, i.e., as you draw a line from one dot to another, you'd see a constantly changing number representing the current distance of the connecting line. Also, once lines are connected to form a rectangle, would be cool to be able to write something within that rectangle. Then one could really create diagrams, which would be pretty cool.

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  • How to get levels for Fry Graph readability formula?

    - by Vic
    Hi, I'm working in an application (C#) that applies some readability formulas to a text, like Gunning-Fog, Precise SMOG, Flesh-Kincaid. Now, I need to implement the Fry-based Grade formula in my program, I understand the formula's logic, pretty much you take 3 100-words samples and calculate the average on sentences per 100-words and syllables per 100-words, and then, you use a graph to plot the values. Here is a more detailed explanation on how this formula works. I already have the averages, but I have no idea on how can I tell my program to "go check the graph and plot the values and give me a level." I don't have to show the graph to the user, I only have to show him the level. I was thinking that maybe I can have all the values in memory, divided into levels, for example: Level 1: values whose sentence average are between 10.0 and 25+, and whose syllables average are between 108 and 132. Level 2: values whose sentence average are between 7.7 and 10.0, and .... so on But the problem is that so far, the only place in which I have found the values that define a level, are in the graph itself, and they aren't too much accurate, so if I apply the approach commented above, trying to take the values from the graph, my level estimations would be too much imprecise, thus, the Fry-based Grade will not be accurate. So, maybe any of you knows about some place where I can find exact values for the different levels of the Fry-based Grade, or maybe any of you can help me think in a way to workaround this. Thanks

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  • How to determine Scale of Line Graph based on Pixels/Height?

    - by Dexter
    I have a problem due to my terrible math abilities, that I cannot figure out how to scale a graph based on the maximum and minimum values so that the whole graph will fit onto the graph-area (400x420) without parts of it being off the screen (based on a given equation by user). Let's say I have this code, and it automatically draws squares and then the line graph based on these values. What is the formula (what do I multiply) to scale it so that it fits into the small graphing area? vector<int> m_x; vector<int> m_y; // gets automatically filled by user equation or values int HeightInPixels = 420;// Graphing area size!! int WidthInPixels = 400; int best_max_y = GetMaxOfVector(m_y); int best_min_y = GetMinOfVector(m_y); m_row = 0; m_col = 0; y_magnitude = (HeightInPixels/(best_max_y+best_min_y)); // probably won't work magnitude = (WidthInPixels/(int)m_x.size()); m_col = m_row = best_max_y; // number of vertical/horizontal lines to draw ////x_magnitude = (WidthInPixels/(int)m_x.size())/2; Doesn't work well ////y_magnitude = (HeightInPixels/(int)m_y.size())/2; Doesn't work well ready = true; // we have values, graph it Invalidate(); // uses WM_PAINT

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  • How to use Facebook graph API to retrieve fan photos uploaded to wall of fan page?

    - by Joe
    I am creating an external photo gallery using PHP and the Facebook graph API. It pulls thumbnails as well as the large image from albums on our Facebook Fan Page. Everything works perfect, except I'm only able to retrieve photos that an ADMIN posts to our page. (graph.facebook.com/myalbumid/photos) Is there a way to use graph api to load publicy uploaded photos from fans? I want to retrieve the pictures from the "Photos from" album, but trying to get the ID for the graph query is not like other albums... it looks like this: http://www.facebook.com/media/set/?set=o.116860675007039 Another note: The only way i've come close to retreiving this data is by using the "feed" option.. ie: graph.facebook.com/pageid/feed EDIT: This is about as far as I could get- it works, but has certain issues stated below. Maybe someone could expand on this, or provide a better solution. (Using FB PHP SDK) <?php require_once ('config.php'); // get all photos for album $photos = $facebook->api("/YourID/tagged"); $maxitem =10; $count = 0; foreach($photos['data'] as $photo) { if ($photo['type'] == "photo"): echo "<img src='{$photo['picture']}' />", "<br />"; endif; $count+= 1; if ($count >= "$maxitem") break; } ?> Issues with this: 1) The fact that I don't know a method for graph querying specific "types" of Tags, I had to run a conditional statement to display photos. 2) You cannot effectively use the "?limit=#" with this, because as I said the "tagged" query contains all types (photo, video, and status). So if you are going for a photo gallery and wish to avoid running an entire query by using ?limit, you will lose images. 3) The only content that shows up in the "tagged" query is from people that are not Admins of the page. This isn't the end of the world, but I don't understand why Facebook wouldn't allow yourself to be shown in this data as long as you posted it "as yourself" and not as the page.

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  • How do I serialise a graph in Java without getting StackOverflowException?

    - by Tim Cooper
    I have a graph structure in java, ("graph" as in "edges and nodes") and I'm attempting to serialise it. However, I get "StackOverflowException", despite significantly increasing the JVM stack size. I did some googling, and apparently this is a well known limitation of java serialisation: that it doesn't work for deeply nested object graphs such as long linked lists - it uses a stack record for each link in the chain, and it doesn't do anything clever such as a breadth-first traversal, and therefore you very quickly get a stack overflow. The recommended solution is to customise the serialisation code by overriding readObject() and writeObject(), however this seems a little complex to me. (It may or may not be relevant, but I'm storing a bunch of fields on each edge in the graph so I have a class JuNode which contains a member ArrayList<JuEdge> links;, i.e. there are 2 classes involved, rather than plain object references from one node to another. It shouldn't matter for the purposes of the question). My question is threefold: (a) why don't the implementors of Java rectify this limitation or are they already working on it? (I can't believe I'm the first person to ever want to serialise a graph in java) (b) is there a better way? Is there some drop-in alternative to the default serialisation classes that does it in a cleverer way? (c) if my best option is to get my hands dirty with low-level code, does someone have an example of graph serialisation java source-code that can use to learn how to do it?

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  • Finding a Eulerian Tour

    - by user590903
    I am trying to solve a problem on Udacity described as follows: # Find Eulerian Tour # # Write a function that takes in a graph # represented as a list of tuples # and return a list of nodes that # you would follow on an Eulerian Tour # # For example, if the input graph was # [(1, 2), (2, 3), (3, 1)] # A possible Eulerian tour would be [1, 2, 3, 1] I came up with the following solution, which, while not as elegant as some of the recursive algorithms, does seem to work within my test case. def find_eulerian_tour(graph): tour = [] start_vertex = graph[0][0] tour.append(start_vertex) while len(graph) > 0: current_vertex = tour[len(tour) - 1] for edge in graph: if current_vertex in edge: if edge[0] == current_vertex: current_vertex = edge[1] else: current_vertex = edge[0] graph.remove(edge) tour.append(current_vertex) break return tour graph = [(1, 2), (2, 3), (3, 1)] print find_eulerian_tour(graph) >> [1, 2, 3, 1] However, when submitting this, I get rejected by the grader. I am doing something wrong? I can't see any errors.

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  • How to generate portal zones?

    - by Meow
    I'm developing a portal-based scene manager. Basically all it does is to check the portals against the camera frustum, and render their associated portal zones accordingly. Is there any way my editor can generate portal zones automatically with the user having to set the portals themselves only? For example, the Max Payne 1/2 engine ("Max-FX") only required to set the portal quads, unlike the C4 engine where you also have to explicitly set the portal zones.

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  • help in the Donalds B. Johnson's algorithm, i cannot understand the pseudo code (PART II)

    - by Pitelk
    Hi all , i cannot understand a certain part of the paper published by Donald Johnson about finding cycles (Circuits) in a graph. More specific i cannot understand what is the matrix Ak which is mentioned in the following line of the pseudo code : Ak:=adjacency structure of strong component K with least vertex in subgraph of G induced by {s,s+1,....n}; to make things worse some lines after is mentins " for i in Vk do " without declaring what the Vk is... As far i have understand we have the following: 1) in general, a strong component is a sub-graph of a graph, in which for every node of this sub-graph there is a path to any node of the sub-graph (in other words you can access any node of the sub-graph from any other node of the sub-graph) 2) a sub-graph induced by a list of nodes is a graph containing all these nodes plus all the edges connecting these nodes. in paper the mathematical definition is " F is a subgraph of G induced by W if W is subset of V and F = (W,{u,y)|u,y in W and (u,y) in E)}) where u,y are edges , E is the set of all the edges in the graph, W is a set of nodes. 3)in the code implementation the nodes are named by integer numbers 1 ... n. 4) I suspect that the Vk is the set of nodes of the strong component K. now to the question. Lets say we have a graph G= (V,E) with V = {1,2,3,4,5,6,7,8,9} which it can be divided into 3 strong components the SC1 = {1,4,7,8} SC2= {2,3,9} SC3 = {5,6} (and their edges) Can anybody give me an example for s =1, s= 2, s= 5 what if going to be the Vk and Ak according to the code? The pseudo code is in my previous question in http://stackoverflow.com/questions/2908575/help-in-the-donalds-b-johnsons-algorithm-i-cannot-understand-the-pseudo-code and the paper can be found at http://stackoverflow.com/questions/2908575/help-in-the-donalds-b-johnsons-algorithm-i-cannot-understand-the-pseudo-code thank you in advance

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  • TypeError: can't convert String into Integer

    - by demas
    I have code: class Scene def initialize(number) @number = number end attr_reader :number end scenes = [Scene.new("one"), Scene.new("one"), Scene.new("two"), Scene.new("one")] groups = scenes.inject({}) do |new_hash, scene| new_hash[scene.number] = [] if new_hash[scene.number].nil? new_hash[scene.number] << scene end When I'm lauching it I get error: freq.rb:11:in `[]': can't convert String into Integer (TypeError) from freq.rb:11:in `block in <main>' from freq.rb:10:in `each' from freq.rb:10:in `inject' from freq.rb:10:in `<main>' If I change scenes to: scenes = [Scene.new(1), Scene.new(1), Scene.new(2), Scene.new(1)] the problem dissapear. Why I get error message in the first case? Why Ruby decide to convert scene.number from String to Integer? And one additional question about the 'inject' method. When Ruby initialize the 'new_hash' variable and how can Ruby know the type of this variable?

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  • Reading graph inputs for a programming puzzle and then solving it

    - by Vrashabh
    I just took a programming competition question and I absolutely bombed it. I had trouble right at the beginning itself from reading the input set. The question was basically a variant of this puzzle http://codercharts.com/puzzle/evacuation-plan but also had an hour component in the first line(say 3 hours after start of evacuation). It reads like this This puzzle is a tribute to all the people who suffered from the earthquake in Japan. The goal of this puzzle is, given a network of road and locations, to determine the maximum number of people that can be evacuated. The people must be evacuated from evacuation points to rescue points. The list of road and the number of people they can carry per hour is provided. Input Specifications Your program must accept one and only one command line argument: the input file. The input file is formatted as follows: the first line contains 4 integers n r s t n is the number of locations (each location is given by a number from 0 to n-1) r is the number of roads s is the number of locations to be evacuated from (evacuation points) t is the number of locations where people must be evacuated to (rescue points) the second line contains s integers giving the locations of the evacuation points the third line contains t integers giving the locations of the rescue points the r following lines contain to the road definitions. Each road is defined by 3 integers l1 l2 width where l1 and l2 are the locations connected by the road (roads are one-way) and width is the number of people per hour that can fit on the road Now look at the sample input set 5 5 1 2 3 0 3 4 0 1 10 0 2 5 1 2 4 1 3 5 2 4 10 The 3 in the first line is the additional component and is defined as the number of hours since the resuce has started which is 3 in this case. Now my solution was to use Dijisktras algorithm to find the shortest path between each of the rescue and evac nodes. Now my problem started with how to read the input set. I read the first line in python and stored the values in variables. But then I did not know how to store the values of the distance between the nodes and what DS to use and how to input it to say a standard implementation of dijikstras algorithm. So my question is two fold 1.) How do I take the input of such problems? - I have faced this problem in quite a few competitions recently and I hope I can get a simple code snippet or an explanation in java or python to read the data input set in such a way that I can input it as a graph to graph algorithms like dijikstra and floyd/warshall. Also a solution to the above problem would also help. 2.) How to solve this puzzle? My algorithm was: Find shortest path between evac points (in the above example it is 14 from 0 to 3) Multiply it by number of hours to get maximal number of saves Also the answer given for the variant for the input set was 24 which I dont understand. Can someone explain that also. UPDATE: I get how the answer is 14 in the given problem link - it seems to be just the shortest path between node 0 and 3. But with the 3 hour component how is the answer 24 UPDATE I get how it is 24 - its a complete graph traversal at every hour and this is how I solve it Hour 1 Node 0 to Node 1 - 10 people Node 0 to Node 2- 5 people TotalRescueCount=0 Node 1=10 Node 2= 5 Hour 2 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5(Rescued) Node 0 to Node 1 = 10 Node 0 to Node 2 = 5 Node 1 to Node 2 = 4 TotalRescueCount = 10 Node 1 = 10 Node 2= 5+4 = 9 Hour 3 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5+4 = 9(Rescued) TotalRescueCount = 9+5+10 = 24 It hard enough for this case , for multiple evac and rescue points how in the world would I write a pgm for this ?

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