Tag: numbers

First, Vector should not be used here. It's essentially a synchronized ArrayList, and you do not need synchronization in this case. Just change to one ArrayList.

This has the potential to be a little faster.

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Second, you use a crude ArrayList which is not typesafe:

list.add ("Some nonsense"); // does not cause an error

and requires your (Int) typing later. Indicate that the list contains integers using generics and that it will be secure. Read it < > like "from" here:

// Note how we specify what the list can contain
// A list of tables of integers
ArrayList list = new ArrayList <> ();

list.add ("Some nonsense") // This causes an error now when compiling

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You also do strange things with the full manufacturer. You do not need to manually convert unframed integers such as Whole (2). 2 will be "automatically boxed" in its object wrapper if needed implicitly.

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You call Whole / parseInt apart from one try; which is risky. If the user enters a wrong entry, your entire program is blocked. Wrap it up and manage the failures (yes, users will enter a bad entry):

try {
intene = Integer.parseInt (n);
// Code using "ene"

} catch (NumberFormatException e) {
// Just an example. You will need to do something more involved, like asking again
System.out.println ("Failed to scan");
}

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Just as an example of what I mentioned earlier:

static vacuum exchange (ArrayList arr, int k) {
...
int one = (int) arr.get (j);
int two = (int) arr.get (j + half);
Integer number_test = new Integer (one + two);

Make the setting generic, and eliminate throws and boxing. Write:

static vacuum exchange (ArrayList arr, int k) {
...
int one = arr.get (j);
int two = arr.get (j + half);
int number_test = one + two;

And then similarly below that.

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In addition, Java prefers camelCase, not snake_case. It is best to respect the conventions of the language you use.

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import java.sql.Date;

is a bit disturbing. You should not really loot a SQL library just to use a date object. Java has a java.time package for this purpose.

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Just like a tip,

int two;
if (j + 1 == arr.size ()) {
two = arr.get (0);

} other {
two = arr.get (j + 1);
}

Can also be written as:

int two = j + 1 == arr.size ()? arr.get (0): arr.get (j + 1);

Or:

int two = arr.get (j + 1 == arr.size ()? 0: j + 1);

Depending on the duplication you can tolerate. the ? : a part is called a "ternary operator" / a "conditional expression".

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if (! bonus.contains (number_test)) {

It's quite expensive when you do it on a listing like a ArrayList. If you need to use contains, you should Probably use a Together like a HashSet. Membership searches are a lot faster using sets. The time difference will become more and more perceptible the first ones expands.