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Java Program to create a TreeSet with custom Comparator
To create a TreeSet with custom comparator, let us first create a an Integer array and set it to TreeSet
Integer arr[] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 };
Set<Integer> set = new TreeSet<Integer>(Collections.reverseOrder());Above, we have used the Comparator with reverseOrder(), which returns a comparator that imposes the reverse of the natural ordering.
Example
import java.util.Collections;
import java.util.Set;
import java.util.TreeSet;
public class Demo {
public static void main(String args[]) throws Exception {
Integer arr[] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 };
Set<Integer> set = new TreeSet<Integer>(Collections.reverseOrder());
for (int i = 0, n = arr.length; i < n; i++) {
set.add(arr[i]);
}
System.out.println("TreeSet = "+set);
System.out.println(((TreeSet<Integer>) set).comparator());
}
}Output
TreeSet = [100, 90, 80, 70, 60, 50, 40, 30, 20, 10] java.util.Collections$ReverseComparator@6276ae34
Updated on: 30-Jul-2019
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