Java by API/java.util/TreeSet

new TreeSet(Collection<?> c)

  

import java.util.Arrays;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet<String> set = new TreeSet<String>(Arrays.asList(elements));
    System.out.println(set.headSet("D"));
    System.out.println(set.tailSet(""));
  }
}

new TreeSet < E > ()

  
/**
 *Output: 
 [A, B, C, D, E, F]
 */
import java.util.TreeSet;
public class MainClass {
  public static void main(String args[]) {
    TreeSet<String> ts = new TreeSet<String>();
    ts.add("C");
    ts.add("A");
    ts.add("B");
    ts.add("E");
    ts.add("F");
    ts.add("D");
    System.out.println(ts);
  }
}

new TreeSet < E > (Comparator < ? super)

  
/**
 *Output: 
 F E D C B A 
  */
import java.util.ruparator;
import java.util.TreeSet;
class MyComparator implements Comparator<String> {
  public int compare(String a, String b) {
    String aStr, bStr;
    aStr = a;
    bStr = b;
    return bStr.rupareTo(aStr);
  }
  // No need to override equals.
}
public class MainClass {
  public static void main(String args[]) {
    TreeSet<String> ts = new TreeSet<String>(new MyComparator());
    ts.add("C");
    ts.add("A");
    ts.add("B");
    ts.add("E");
    ts.add("F");
    ts.add("D");
    for (String element : ts)
      System.out.print(element + " ");
    System.out.println();
  }
}

TreeSet: add(E o)

  
/**
 *Output: 
 [A, B, C, D, E, F]
 */
import java.util.TreeSet;
public class MainClass {
  public static void main(String args[]) {
    TreeSet<String> ts = new TreeSet<String>();
    ts.add("C");
    ts.add("A");
    ts.add("B");
    ts.add("E");
    ts.add("F");
    ts.add("D");
    System.out.println(ts);
  }
}

TreeSet: comparator()

  
import java.util.Collections;
import java.util.Set;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    Set<String> set = new TreeSet<String>(Collections.reverseOrder());
    for (int i = 0, n = elements.length; i < n; i++) {
      set.add(elements[i]);
    }
    System.out.println(set);
    System.out.println(((TreeSet) set).ruparator());
  }
}

TreeSet: first()

  
import java.util.Arrays;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet<String> set = new TreeSet<String>(Arrays.asList(elements));
    System.out.println(set);
    System.out.println(set.first());
    System.out.println(set.last());
  }
}

TreeSet: headSet(T toElement)

  

import java.util.Arrays;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet<String> set = new TreeSet<String>(Arrays.asList(elements));
    System.out.println(set.headSet("D"));
    System.out.println(set.tailSet(""));
  }
}

TreeSet: last()

  
import java.util.Arrays;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet<String> set = new TreeSet<String>(Arrays.asList(elements));
    System.out.println(set);
    System.out.println(set.first());
    System.out.println(set.last());
  }
}

TreeSet: remove(Object o)

 
import java.util.TreeSet;
public class Main {
  public static void main(String[] args) {
    TreeSet<Integer> tSet = new TreeSet<Integer>();
    System.out.println("Size of TreeSet : " + tSet.size());
    tSet.add(new Integer("1"));
    tSet.add(new Integer("2"));
    tSet.add(new Integer("3"));
    System.out.println(tSet.size());
    // remove one element from TreeSet using remove method
    tSet.remove(new Integer("1"));
    System.out.println("Size of TreeSet after removal : " + tSet.size());
  }
}

TreeSet: subSet(T fromElement, T toElement)

  

import java.util.Arrays;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet<String> set = new TreeSet<String>(Arrays.asList(elements));
    System.out.println(set.subSet("C", "F"));
  }
}

TreeSet: tailSet(T fromElement)

  

import java.util.Arrays;
import java.util.TreeSet;
public class Main {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet<String> set = new TreeSet<String>(Arrays.asList(elements));
    System.out.println(set.headSet("D"));
    System.out.println(set.tailSet(""));
  }
}