A data structure is a way of organizing data in a fashion that allows particular properties of that data to be queried and/or updated efficiently.
1
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0answers
24 views
Concurrent hash map for memoization
I'm developing a concurrent hash map for DP memoization. The assumptions behind its design are the following:
no erase operations are possible
once the value corresponding to a key is written, it is ...
1
vote
0answers
68 views
What is this structure called?
So I've been writing this data structure for a few days, and now I'm really curious about what it actually is, and to get some critique on my logic.
A branch, based on this usage, exists when a HEAD ...
1
vote
2answers
54 views
Correct way to delete elements from a ConcurrentDictionary with a predicate
I have written a caching wrapper class for ConcurrentDictionary. Basically it has a timer that checks if items are expired and removes them. Since ConcurrentDictionary does not have RemoveAll method ...
3
votes
1answer
57 views
Writing/reading data structure to a file using C++
I wrote some piece of code which reads and write multiple data structures on a file
using C++. I would be grateful to get your feedback on what you think about the code (it works at least when I ...
1
vote
1answer
65 views
Create palindrome by rearranging letters of a word
Inspired by a recent question that caught my interest, I wrote a function in Python 3.3 to rearrange the letters of a given string to create a (any!) palindrome:
Count the occurrences of each letter ...
0
votes
1answer
75 views
Dictionary Structure
I am brand new to dictionaries and coding and am hoping to get some suggestions on how I should structure my dictionary.
I have a collector number which has meters connected to them. Each of the ...
1
vote
2answers
80 views
Check if a Binary Tree <String> is aBinary Search Tree
i'm understanding the question but wanna make sure if my implementation is correct or not =|
The Q is :
Write a method that accepts as its argument a BinaryTree object and returns true if the ...
1
vote
1answer
86 views
Singly Linked List (strings only)
This is my attempt at constructing a singly-linked-list with basic functions. I initially tried to build the whole list as a series of nodes, but ran into problems when trying to remove or pop ...
6
votes
4answers
155 views
Readability and Performance of my Trie implementation
As an interesting exercise in Python 3.3, I implemented a Trie (also known as a Prefix Tree).
Example usages
Create from list of key-value-tuples
mapping = (('she', 1), ('sells', 5), ('sea', 10), ...
-1
votes
2answers
82 views
What is a good name for bidirectional dictionary structure? [closed]
I'm writing a generic bidirectional dictionary which will be a part of a (somewhat) public API. This is how the dictionary works:
It will hold key-key pairs where key1 and key2 will be two different ...
1
vote
0answers
30 views
Is this code for getting the dependency tree of a file correct?
function dep_tree(graph,node,prev_deps){
return uniq(flatten(graph[node].map(function(child_node){
if (contains(prev_deps,child_node))
throw "Circular reference between ...
1
vote
1answer
98 views
Remove Nth Node From End of List
Given a linked list, remove the nth node from the end of list and return its head.
For example,
Given linked list: 1->2->3->4->5, and n = 2.
After removing the second node from the end, the ...
1
vote
2answers
39 views
Mapping enum to enum - is this an efficient and elegant implementation
I need to map from one enum type to another. Here is the enum I am
given:
enum CfgFruitType { CFGNoFruit, CFGApple, CFGApricot, CFGBanana,
CFGMango, CFGKiwi, CFGFig, CFGGrape, CFGMelon, CFGLemon,
...
1
vote
1answer
41 views
Refactor making a tree with hash input?
I initialized a tree using a nested hash as input, but when I recursively call Tree.new on the children, it doesn't seem to pass each child as a hash. As a pretty ugly, but working, alternative, I ...
1
vote
1answer
56 views
Double linked list with different dependencies
I need to connect different Task with a double linked list and different Dependencies which affect a calculation for which I need the values of both Task:
public class Task {
private ...
1
vote
2answers
98 views
remove all nodes with same value in a linked list
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return ...
1
vote
3answers
110 views
remove duplicates from linked list
Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
The following is my code:
...
0
votes
1answer
53 views
2D Array: Retrieve the “Left” Item
I am creating a game that contains a Board and Pieces. The Board is basically a 2D array of Pieces. [Think smaller chess board]
One of the things that I want to accomplish is to be able to retrieve ...
6
votes
3answers
356 views
Two Key HashMap
Background
Would like to create a two-key map that is fairly generic. In the existing system, there are a number of ways to name a parameter for a report. Rather than re-writing each report (too much ...
2
votes
2answers
107 views
Need a suggestion for invert index structure in C++
I am trying to create an invert index structure in C++. An invert index, in this case, refers to image retrival system, where each invert index refers to a numbers of "Patch ID". (simply called "ID" ...
5
votes
1answer
118 views
STL-style deque class, please critique
I'm a C++ newb. I decided to write an STL-style class as an exercise. I followed a tutorial of sorts that I found online, but I also made some modifications. I'd like to hear any criticisms you folks ...
4
votes
1answer
80 views
Improving a priority queue sketch in Racket/Scheme
I just put together the skeletons for a priority queue using a binary heap in racket/scheme. Using racket/scheme is all about the educational experience and I was wondering if anyone wants to ...
4
votes
1answer
116 views
Need help optimizing orthogonal range search for a static kd tree
I'm trying to optimise my implemention of a static kd tree to perform orthogonal range searches in c++.
My problem: The code performs slowly even for a small number of queries when the number of ...
1
vote
1answer
73 views
Standard Library-Like Linear Interpolation Table
Looking for a general review of a generalized linear interpolation table. Design decisions, anything that's missing, anything that could be clearer or simplified, any style considerations. Keep in ...
0
votes
0answers
69 views
Mapping ReadOnlyObservableCollection to another collection
I'm writing a WPF application and I have several ReadOnlyObservableCollection fields in my models.
Suppose that I wanted to create a FooViewModel instance for each FooModel instance.
FooModel has an ...
3
votes
1answer
64 views
delete a key in a trie
To delete a key from a trie, there are four cases:
For the explanation of trie data structure, please check
the following link:
http://www.geeksforgeeks.org/trie-insert-and-search/
(1) Key is not in ...
1
vote
2answers
109 views
How can this code become cleaner and less error prone? Especially the binary search part
How could this code become cleaner?
I think that the way I handle the interfaces and binary search could be improved.
I am trying to understand how to structure such a code 9and usage of APIs) in a ...
1
vote
2answers
88 views
Partition a linked list arround an element
This is my code to partition a list into two parts according to a value. I.e. nodes smaller than value x should precede nodes larger than the value x.
It seems correct. Any corner cases I am ...
2
votes
1answer
220 views
Returning Binary Search Tree Nodes in Zig Zag manner
I tried to implement an answer for the algorithm question given below. I implemented two different solutions. I couldn't decide which one is better. ( Maybe none )
Note: Node class and ZigZag ...
2
votes
2answers
142 views
Undirected, connected and weighted graph implementation
I was thinking in a way of implementing a graph in such that would let find a minimum spanning tree.
I have this:
Graph.h
#ifndef GRAPH_H
#define GRAPH_H
#include <list>
#include ...
2
votes
2answers
169 views
A* shortest path algorithm optimization request
Good day to ya'll. I had this programming excericise of mine where I had to find the shortest path to an exit in an NxM -grid maze in under a second (both N and M would be anywhere between 3 and ...
1
vote
0answers
357 views
Breadth- and Depth-first search code
Here is my breadth-first search (bfs) and depth-first search (dfs) code for graph traversal. Please give me some constructive reviews on it.
Thanks for any help.
#include<stdio.h>
...
1
vote
1answer
150 views
Is this a valid implementation of trie Data structure?
i am trying to learn Trie Data Structure and just implemented it without giving much attention to the code standards , its a raw implementation , can you guys help me to understand whether this ...
0
votes
3answers
190 views
Using a Dedicated Class & Constructor to initialize Stored Procedure for SQL Transaction
as i thought it will be sutible as a Quetion for SO...
i started to describe the issue of my Problem, though as i completed Editing the post , i could see that it will better fit here, In CR.
so to ...
3
votes
2answers
462 views
Inverse Document Frequency (IDF) implementation
I would like to share my class IDF with experts. Sorry for the poor data structure, but we are humans and still learning.
Any Suggestion/ Modification please ?? many Thanks.
public class IDFMeasure
...
2
votes
0answers
72 views
JavaScript basic game code structure tips
I'm learning JavaScript and came up with this basic game code structure (using the CreateJS framework):
var stage;
var totalLoaded = 0;
var manifest;
var game = game || {};
game.init = {
...
0
votes
2answers
84 views
How can I improve the run-time of my Java program?
I have a project for solving Diophantine equations, where a solution exists if
A^5 + B^5 + C^5 + D^5 + E^5 = F^5, where 0 < A <= B <= C <= D <=E <=
F <= N
The program ...
2
votes
1answer
241 views
Objective-C Stack implementation
I'm a S.O. user, and this is my first question on Code Review, so please be lenient. (i actually thought about making a site like this myself at one point, but i LOVE this Code Review idea!).
I just ...
6
votes
2answers
263 views
Which is the most correct pattern for using Stack.Pop?
There at least 2 patterns of using Stack.Pop
private Stack<T> availableResources;
...
if (availableResources.Count > 0)
{
resource = availableResources.Pop();
...
}
private ...
2
votes
3answers
121 views
How to make a program bettter. Does it come with experience?
Hi guys look at the code given below. It is from my class work. It is a simple demonstration of a singly linked list.
#include <stdio.h>
#include <stdlib.h>
#include <wctype.h>
...
5
votes
1answer
276 views
How can I improve my algorithm?
This is a problem from Interview Street in Dynamic Programming section.
https://www.interviewstreet.com/challenges/dashboard/#problem/4f2c2e3780aeb
Billboards(20 points)
ADZEN is a very ...
5
votes
2answers
362 views
In Java, how to operate the sublists efficiently?
In my Java program, I need to operate on the sublists a of ArrayList or LinkedList often, like removing a sublist, comparing two sublists.
For ArrayList or LinkedList, I didn't find any good APIs to ...
5
votes
1answer
99 views
Sparse Bitarray Class in Python (or rather frequently having contiguous elements with the same value)
Sparse is probably the wrong word - this is for encoding arrays of booleans where contiguous values tend to be the same. It'd be great to know a proper name for this data structure so I could read ...
9
votes
3answers
279 views
Reversing a linked list
I implemented reversing a linked list in iterative way, just by knowing we need 3 pointers and I have never seen a code before, when I coded. I ran this code and tested it, it works fine. Even for ...
7
votes
0answers
293 views
Scala: Disjoint-Sets
I would like to get some feedback on the following implementation of disjoint sets, based on disjoint-sets forests (Cormen, et.al., Introduction to Algorithms, 2nd ed., p.505ff). It should have the ...
4
votes
1answer
200 views
Partitioning Array
Problem: Given a randomly ordered array of n-elements, partition the
elements into two subsets such that elements <=x are in one subset and
elements > x are in the other subset.
one way to do this ...
5
votes
1answer
814 views
A trie implementation for left to right wild card search
I was working on a task to implement auto suggest from an array of couple of thousands of strings.
Ofcourse the first and the easiest implementable was to go through each element and do ...
3
votes
1answer
211 views
Javascript PriorityQueue based on object property
I am pretty new to javascript development and its temperaments. I wrote this class which is a priority queue based on a numeric property of any object. As far as I can tell, the following code is ...
5
votes
2answers
1k views
atomic_queue - thread-safe and lock-free implementation of the FIFO data structure pattern
please review my implementation of a FIFO data structure that guarantees thread-safe access without locking.
I removed the license header block and all Doxygen comments. The original version (along ...
3
votes
1answer
74 views
mapM for both keys and values of Data.Map
I'm writing a monadic parser instance that transforms Data.Map.Map's:
instance (Ord a, FromEDN a, FromEDN b) => FromEDN (M.Map a b) where
parseEDNv (E.Map m) = mapMmap parseEDNv parseEDN m
...
