I have an ArrayList of ints[] that I would like to sort based on the distance from a specific position.
Example. ArrayList<int[]> = {-2,-3},{2,3}, {1,2}
Specific position = {1,1}
After sorting: {1,2}, {2,3}, {-2,-3}
I know I can just subtract {1,1} from every int[] then create a Comparator for the magnitudes--but my question specifically is how to do it without subtracting {1,1} first.
Make a custom 'translator' function, and then make a comparator to compare on this function:
int[] ORIGIN = {1, 1};
list.sort(Comparator.comparingDouble(a -> distance(ORIGIN, a));
public double distance(int[] a, int[] b) {
// not sure how one calculates this distance thing,
// but do it here
}
distance() method should be static, and you calculate distance between two points like normally, i.e. square root of sum of squares: sqrt( (a[0] - b[0])^2 + (a[1] - b[1])^2 ) where ^2 means squared. Since you are comparing the results relatively, the sqrt part can be skipped, for better performance.