hashtable

问题 I am using an unordered_map>float, unsigned short> to implement a hash table in C++. I know that using floats as keys to a hash table is a BAD idea under most circumstances because comparing them is error prone. However, under these circumstances I am reading the floats in from large files and their precision is known and constant. However, I would like to know the details of how unordered_map is hashing my floats in order to estimate collision frequency. I am not overriding the default hash

问题 I'm new to C++, and I just can't seem to figure out what's causing these errors. The following is my header file: #ifndef TABLE #define TABLE #include <iostream> #include <cstdlib> #include <vector> typedef struct { double successful , unsuccessful[2] ; } Perform ; using namespace std ; template <class DATA> class Table { private : vector<DATA>* slot; vector<bool>* passBits; vector<bool>* full; int tableSize; public : explicit Table ( unsigned size = 5 ) ; ~Table( ) ; //destructor void empty

问题 I need to do : Dictionary cache; cache = new Hashtable(); this.getDocument().putProperty("imageCache", cache); Then I have a method who does : cache.put(url, picture); Where picture is an Image object. I create this way : public Image getSmiley(String smileyName) { BufferedImage img = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB); Graphics g = img.getGraphics(); ImageIcon myicon = new ImageIcon(getClass().getResource("/ola/smileys/" + smileyName + ".png")); myicon.paintIcon(null, g,

问题 I have two text files with comma delimited values. One is 150MB and the other is 370MB, so these guys have three million+ rows of data. One document holds information about, let's say soft drink preferences, and the next might have information about, let's say hair colors. Example soft drinks data file, though in the real file the UniqueNames are NOT in order, nor are the dates: "UniqueName","softDrinkBrand","year" "001","diet pepsi","2004" "001","diet coke","2006" "001","diet pepsi","2004"

问题 I have a large database (approx. 150 000 records) that I want to embed into an OCaml source code named compute.ml. I am trying (without success) to transform these tables into hashtables and to embed these hastables into a function compute , so as to have the binary program run quicly without having to do queries to an external sql database. I have 2 questions: Is there a way to export for once a mysql table into an associative array (Hashtbl) that can be accessed by (or even embedded into)

问题 So the question came up about whether tombstones should be included when calculating the load factor of a hash table. I thought that, given that the load factor is used to determine when to expand capacity, tombstones should not be included. An obvious example is if you almost fill and then remove every value in a hash table. Here insertions are super easy (no collisions) so I believe the load factor shouldn't include them. But you could look at this and think that with all the tombstones

问题 I am having a weird issue with serialization of a Hashtable. I have made a Server, Client app. Where server(PC/MAC) is serializing a Hashtable and sending it to Client(Android) through UDP. The data is sent/read correctly but I get a bunch of these messages below on LogCat. 04-12 11:19:43.059: DEBUG/dalvikvm(407): GetFieldID: unable to find field Ljava/util/Hashtable;.loadFactor:F Occasionally, I would see these 04-12 11:21:19.150: DEBUG/dalvikvm(407): GC freed 10814 objects / 447184 bytes in

问题 I'm developing tool, which takes Java code and generate code for getting estimations for execution time of basic blocks, loops and methods. After some block is executed, we put it's time to our tool. The program model is stored in next representation static Hashtable<String, Hashtable<Integer, Hashtable<String, pair>>> method2Data = new Hashtable<String, Hashtable<Integer, Hashtable<String, pair>>>(); static Hashtable<String, Vector<String>> class2Method = new Hashtable<String, Vector<String>

问题 I have a very strange error in this code from Vaadin's ContainerHierarchicalWrapper: for (Object object : children.keySet()) { LinkedList<Object> object2 = children.get(object); } The debugger shows this state: How is that even possible? How can object2 be null ? This is my actual code which causes the NPE (class EstablishRelationWindow ): childrenContainer = new BeanItemContainer<>(PlaylistDTO.class); childrenContainerHierarchy = new ContainerHierarchicalWrapper(childrenContainer);

问题 I'm essentially trying to create a list of pairs which is proving frustratingly difficult Note before anyone mentions Hashtables that there will be duplicates which I don't care about. For example, if I do $b = @{"dog" = "cat"} I get Name Value ---- ----- dog cat which is good. However, I'm then unable to add the likes of $b += @{"dog" = "horse"} Item has already been added. Key in dictionary: 'dog' Key being added: 'dog' I'm just trying to create a table of data which I can add to using