All Questions
31 questions
-1
votes
1
answer
111
views
How to efficiently search an element in a TreeSet without using contains?
I'm quite new to Java and its libraries so its possible this question comes as a dumb or obvious one.
Assuming I have a class like this:
public class Person implements Comparable<Person>
{
...
- 1
2
votes
0
answers
440
views
Java ConcurrentHashMap iterating via entrySet vs keySet
Many articles compare these approaches and all are in favor of entrySet over keySet. All of them take into account the speed, but none heap usage.
https://coderanch.com/t/203203/java/entrySet-keySet-...
- 20.2k
0
votes
1
answer
152
views
How to iterate through a fixed tridimensional matrix efficiently (java)
As part of a program I'm building I need to iterate through all the points in a tridimensional matrix.
On each point I need to execute a method that takes int x, int y, int z as parameters.
The ...
- 504
1
vote
2
answers
685
views
Is using Pattern/Matcher more efficient than looping through a string and looking for characters?
I am working on a project that will look through a java file for a particular method, and output the lines that method occupies to a file. I am already using a Pattern and Matcher to find the method, ...
- 402
-2
votes
5
answers
1k
views
List are given in map<key,values> as values,how can I find one or more key which have largest list size java
I have written a method which returns a map.
The structure of the map is:
Map<String, List<String>> map;
The map can contain more than 1000 keys, and each key can contain a list more than ...
- 13
1
vote
5
answers
3k
views
Whats the performance cost on iterating on a list multiple times
I have a List I need to iterate through and perform work on along the way. My problem is that, for my program, its difficult to do all the work needed on the list every loop due to concurrency. My ...
- 2,006
1
vote
1
answer
56
views
Iteration run faster for "even teams" code
I am coding to create two "even teams" based on the players' scores (puntajes).
The algorithm runs through the array of players and compares the score of each one to get a minimum difference and ...
- 11
1
vote
4
answers
378
views
Optimal way to check for common element among many lists?
I understand that ArrayList<>'s are fastest for searching (O(1) vs. O(n)) and LinkedList<>'s are fastest for inserting & deleting (O(1) vs. O(n)).
My question is, if using a ...
- 398
0
votes
1
answer
211
views
Performance: Fastest way to check if a List<String> contains a specific String
In the program I'm writing on, I'll have to check if a List (actually I can replace the type of Collection if necessary) contains a specific String.
Is this the fastest way to do it?
private boolean ...
- 993
7
votes
1
answer
15k
views
Collection iteration with forEach() in multiple threads or with forEach() and lambdas
Let say I have an array with a thousands independent objects inside. Now I want to pass over each of them and perform the same operation, for instance, change the value of a specific field.
At first ...
- 14.7k
1
vote
1
answer
446
views
Iterator raw type should be used or not? [duplicate]
I was wondering about the difference between this statement :
Iterator<String> it = map.values().iterator();
And this statement :
Iterator it = map.values().iterator();
And Also Why is it a ...
- 53
1
vote
5
answers
112
views
How can I make this more efficient?
My program gives a String answer based on comparisons of Integer input. Would there be a more efficient way of doing this instead of prompting the user 3 separate times and calling numberVerify three ...
- 374
1
vote
1
answer
91
views
Java efficient iterating over char
As a part of my implementation I need to implement iterating over chars as efficient as possible. Here is a part of my source code that I wrote:
public int normalize(char s[], int len) {
for (int ...
- 1,879
2
votes
4
answers
216
views
Substitute statements in code with loops in Java
I have these two pieces of code:
int prevY = 0;
// this is the function InsertionSort applied to i
StdDraw.setPenColor(Color.blue);
for (int i = 1; i <= N; i++) {
int x = i;...
- 287
1
vote
0
answers
89
views
Why does this recursive image comparison take less then primitive iterative one? (JAVA 8)
I have run into a little situation that puzzles me. Would someone be able to explain it?
I have written an algorithm in Java that compares two images by first comparing the two middle columns of the ...
- 689