The array tag has no wiki summary.
0
votes
1answer
47 views
Totalising and condensing data values from multiple arrays into a single array
My fledgling programming skills have hit a wall. I could get this working, but the code stinks and I'm convinced there must be a more efficient way I just don't know it yet.
I have a web service ...
0
votes
3answers
145 views
Using action array vs Switch Case
I have an occasion of code in which I will draw a different set of buttons in a screen (depending on the number of the buttons).
One thought (and my current implementation) is to use an action array ...
3
votes
1answer
47 views
Conveniently sorting and (binary?) searching an array of pairs of numbers?
So I have an array of distinct pairs of positive integers. That is, my array looks something like this (for instance):
{ (1,5) , (6,4), (5,3), (2,3), (2,4) }
And my task is, for a given pair (a,b) ...
0
votes
1answer
81 views
Big O notation allocate array of N element
In Big O notation, allocate an array of N element is defined by O(1) or O(n) ?
For example in C#, if I allocate an array like this :
int[] a = new int[10]
When I display this array, I have :
...
0
votes
1answer
23 views
String splits to create arrays
Creating an array of strings for configuration or verification purposes can get long and ugly in code. For example:
arrayOfStrings = ['one','two','three','four']
Often to reduce the characters and ...
0
votes
2answers
51 views
memory management of multi-dimensional array
could you please show me an example how to compute the location of an element in a multi-dimensional array.
It is illustrated in Robert Sebesta's book Concept of Programming Languages that location ...
1
vote
1answer
63 views
How to do “image shifting” faster?
I have a grayscale matrix (implemented as a simple array) to be shown on a display:
line 1: | a | b | c |
line 2: | d | e | f |
a-f are grayscale values. This pattern has to be shifted by a ...
1
vote
2answers
685 views
2D linked list vs. multidimensional array/vector
I hope that programmers is the correct stack exchange for this, as it is quite a concept based question.
I'm working on a data structure in C++ that is a represents data in 3D space. The x-y plane is ...
36
votes
2answers
4k views
How do I move away from the “for-loop” school of thought?
This is a rather conceptual question, but I was hoping I could get some good advice on this. A lot of the programming I do is with (NumPy) arrays; I often have to match items in two or more arrays ...
-1
votes
2answers
177 views
Estimation of space is required to store 275305224 of 5x5 MagicSquares? [closed]
Here are some examples of 5x5 Magic Squares found by some good solvers :
Magic Square Generator by Marcel Roos
this program state using 2.4GHz Intel takes about 95 hours to generate all solutions.
...
0
votes
3answers
176 views
Why is the complexity of fetching a value from an array be O(1)?
How come the complexity of fetching a value from an array by it's index is O(1)?
I thought the algorithm has to go through all the indexes, find the correct index, and then know what value to return. ...
1
vote
2answers
241 views
Why a hashtable? Why not just a non-hashed associative array?
I've been learning about using a hashtable to efficiently check for items in a list without looping through the whole thing, but there's one thing that I don't get:
Why hashed keys?
It seems like:
...
0
votes
1answer
142 views
Why is first column of list called 0th in so many languages? [duplicate]
If you want first element of list or array you reference it as 0 in many languages (like C or Clojure). Is there are some really good reasons why the programming languages was design this way?
In ...
1
vote
1answer
80 views
What is the best approach to storing a multi-dimensional array with unknown bounds?
I'm trying to store content scraped from several lyric and chord websites into separate variables into either a multi-dimensional array, or into separate string arrays, but I've been stuck trying some ...
0
votes
1answer
90 views
Design Pattern : Static Array/List in Class Object
I'm a CS alumni, but we didn't learn much by the way of OOP, or Design Patterns. I've heard the phrase C with iostreams and thought it fitting. Anyway that's besides the point. I am just curious about ...
4
votes
4answers
469 views
Why can't C arrays have 0 length?
The C11 standard says the arrays, both sized and variable length "shall have a value greater than zero." What is the justification for not allowing a length of 0?
Especially for variable length ...
1
vote
2answers
421 views
A vector of pointers to different derived classes of the same base class
I am writing a game in C++ which has different enemy types. I have defined a base Enemy class and I also have derived classes enemy1, enemy2 etc.
Now for updating these enemies in each iteration of ...
1
vote
5answers
165 views
What defines the dimensionality of an array?
I know that when we speak about an array having 1, 2, or 4 dimensions, we mean arrays like this:
1: [0]
2: [0,0]
3: [0,0,0]
4: [0,0,0,0]
...
Is the first 'axis' of an array the only thing that ...
29
votes
11answers
7k views
How does the “Fourth Dimension” work with arrays?
Abstract:
So, as I understand it (although I have a very limited understanding), there are three dimensions that we (usually) work with physically:
The 1st would be represented by a line.
The 2nd ...
2
votes
1answer
144 views
Improving the running time of Breadth First Search and Adjacency List creation
We are given an array of integers where all elements are between 0-9. have to start from the 1st position and reach end in minimum no of moves such that we can from an index i move 1 position back and ...
3
votes
2answers
275 views
Data structure for grid with negative indeces
Sorry if this is an insultingly obvious concept, but it's something I haven't done before and I've been unable to find any material discussing the best way to approach it.
I'm wondering what's the ...
1
vote
2answers
173 views
How to construct a cubie representation of a rubik's cube, given an array
Just to get this out of the way, I have seen this, and it is not what I'm looking for.
So, let's say you are programming a Rubik's Cube. (I know, very unoriginal, but bored programmers have to do ...
5
votes
4answers
594 views
Why do arrays in Java not override equals()?
I was working with a HashSet the other day, which has this written in the spec:
[add()] adds the specified element e to this set if this set contains no element e2 such that (e==null ? e2==null : ...
2
votes
1answer
241 views
Why does Java support brackets behind variables and even behind method signatures? [closed]
Java allows this:
class X{
int i,j[]; // j is an array, i is not
}
and even worse, it allows this:
class X{
int foo(String bar)[][][] // foo actually returns int[][][]
{ return null; } ...
0
votes
0answers
57 views
Search substring using suffix array (and LCP)
I'm searching for a best way to improve suffix array run time using LCP.
My text (about 2 500 000 chars) seems like: 0ricco0eric0america0polo0....
My thoughs:
SA=suffixArray
char=firstChar(input)
s ...
5
votes
1answer
164 views
At ping, why do we have to do array copying instead of passing on the source array that the client sent to us?
So I have been googling about this OpenSSL heart-bleed thing and somehow sees that it is caused by the heartbeat extension which requires client to ping the server to show its aliveness and it all ...
2
votes
1answer
120 views
Accessing a private array when I have an extension method
I'm trying to make a number of data classes for my C#/XNA game, which would essentially be a wrapper around T[,]:
public interface IGrid<T>
where T : struct
{
Point Size { get; }
T ...
0
votes
1answer
1k views
Is a PHP array an example of a dynamic data structure?
I did my homework, and it says that dynamic data structures are "data structures that change in size as a program needs it to by allocating and de-allocating memory from the heap".
So I was ...
0
votes
1answer
111 views
If a variable containing a function gave the function's return instead of a reference to the function, what would an array of functions return? [closed]
I'm creating a prototype scripting language similar to something like Javascript. In my language, every single reference to a variable is actually a function call (a getter function), whether it has ...
1
vote
3answers
326 views
Choice between 1-dimensional and 2-dimensional array
I'm implementing the Chessboard class to represent the chessboard. I've to implement the transformations (reflections and rotations) on the chess board possible.
The possible transformations includes ...
0
votes
3answers
172 views
Sorting an array when values are decreased by each swap [closed]
Recently in an interview I come across a question:
We have an unsorted array, we need to sort it with minimum number of swap. We have in sort a 'tax' of 1 is deducted from the number we are ...
-1
votes
1answer
129 views
Fortran 90 - How to create a coordinate system
So I need to code a simple program, and I need to define 2D coordinates?
Is there any coordinate system I can use in Fortran?
I was told it might have to be all in arrays? And if so, can anybody ...
0
votes
2answers
336 views
Quick algorithm to find matches between two arrays
I'm faced with the following problem:
I have an array which is produced by the parsing of a yaml file which contains patterns in the following structure.
"Programming books"
Title:
a ...
1
vote
3answers
468 views
How do you read this line of code?
Forgive me for my poor English, me and my friend were doing school homework, suddenly he asked me to read this line of code ptr = &array[1][1][1] (ptr is a pointer to an integer).
He said
...
5
votes
2answers
8k views
Should I use a list or an array?
I'm working on a windows form to calculate UPC for item numbers.
I successfully create one that will handle one item number/UPC at a time, now I want to expand and do it for multiple item ...
0
votes
1answer
80 views
What is a cross-platform way to expose an Array[][] over a webservice? Any JSON nuances to be aware of?
I need to expose an Array[][] to many different clients (iPhone, Android, PC, Unix, etc), and need to make it available over HTTP/s
This brings me to JSON, and makes me wonder how do all the other ...
0
votes
2answers
357 views
PHP SplFixedArray How To Deal With billions of indexes?
I've built a flatfile db system that will work like mini-noSQL system
and it split db to smaller files, and I did a SplFixedArray wrapper for it
with a method for searching usage built on preg_grep.
...
1
vote
3answers
920 views
Arrays vs Objects in view template
I am wondering, in view templates, what would contribute to me choosing between using arrays or objects for getting things printed out in arrays
{{$user->zip_code}} vs {{$user['zip_code']}}
I'm ...
1
vote
4answers
245 views
Is it considered bad practice to access a returned array by a key straight away?
I couldn't think of a good way to word the title, sorry. But what I mean is, is it considered bad practice to do:
print get_array()[2]
over:
output=get_array()
print output[2]
(where get_array() ...
-1
votes
3answers
892 views
Find all lines segments intersections
I have a collection of lines segments, represented by an array.
Ex: [3,7,13,6,9] is 4 line segments: [(3,7)(7,13)] , [(7,13)(13,6)] , [(13,6)(6,9)] , ([6,9)(9,3)]
I want to find all the lines ...
-1
votes
5answers
1k views
Reverse subarray of an array with O(1)
I have an idea how to implement sub array reverse with O(1), not including precalculation such as reading the input. I will have many reverse operations, and I can't use the trivial solution of O(N).
...
3
votes
2answers
169 views
What would be the optimal way to solve a problem like this?
I have a problem where I have to change all the Xs in a 2D array into 0s, and I have to calculate the minimum steps (where a single step consists of changing an entire row or column) required to do ...
2
votes
3answers
245 views
What language has integrated “list insertion” as part of code *syntax*?
Many programming languages permit natural manipulation of strings, and some languages permit the manipulations of lists too.
More often then not (always?), these operations are done as procedure ...
2
votes
6answers
386 views
Settle an Argument: String vs. Array?
True or False: A string is the same thing as an array.
I had an interview the other day and the above question was asked. I said false, but the interviewer said it was actually true. I explained to ...
0
votes
1answer
541 views
Use ruby's array sort() method, or add items in correct place with a binary lookup?
If I am loading a whole load of items (un-ordered words from a file or something) would it be more efficient to load them all to a Ruby array, and then use the built in sort! method or to do a binary ...
0
votes
1answer
330 views
Sort rectangles in a grid based on a comparison of the center point of each
If I have a grid of rectangles and I move one of the rectangles, say above and to the left of another rectangle, how would I resort the rectangles?
Note the rectangles are in an array, so each ...
3
votes
2answers
786 views
CA1819: Properties should not return arrays. Does this happen only with arrays? If yes, why?
I have a question about CA1819 msdn performance warning.
The rule is: Arrays returned by properties are not write-protected, even if the property is read-only. To keep the array tamper-proof, the ...
2
votes
3answers
1k views
Specific reasons to create own array class over using std::array?
What specific conditions or requirements should you create your own array over using std::array?
Here is my background:
I'm developing a small simple library that a small group of people will use ...
2
votes
3answers
760 views
Best way to choose random element from weighted list
I want to create a simple game. Every so often, a power up should appear. Right now the different kinds of power ups are stored in an array.
However, not every power up should appear equally often: ...
1
vote
4answers
200 views
Efficient way of evaluating an array of strings then add to an array in Ruby
I am looking for an efficient way of evaluating an array of strings against a series of rules and then adding them to another array.
For example I have an array of strings:
something
a
1234
#gohere
...
