Java: Get the greatest key strictly less than the given key

Java Collection, TreeMap Exercises: Exercise-17 with Solution

Write a Java program to get the greatest key strictly less than the given key. Return null if there is no such key.

Sample Solution:-

Java Code:

import java.util.*;
import java.util.Map.Entry;  
public class Example17 {  
         public static void main(String args[]) {

  // Create a tree map
  TreeMap < Integer, String > tree_map1 = new TreeMap < Integer, String > ();

  // Put elements to the map 
  tree_map1.put(10, "Red");
  tree_map1.put(20, "Green");
  tree_map1.put(40, "Black");
  tree_map1.put(50, "White");
  tree_map1.put(60, "Pink");

  System.out.println("Orginal TreeMap content: " + tree_map1);
  System.out.println("Checking the entry for 10: ");
  System.out.println("Key(s): " + tree_map1.lowerKey(10));
  System.out.println("Checking the entry for 20: ");
  System.out.println("Key(s): " + tree_map1.lowerKey(20));
  System.out.println("Checking the entry for 70: ");
  System.out.println("Key(s): " + tree_map1.lowerKey(70));

Sample Output:

Orginal TreeMap content: {10=Red, 20=Green, 40=Black, 50=White, 60=Pink
Checking the entry for 10:                                             
Key(s): null                                                           
Checking the entry for 20:                                             
Key(s): 10                                                             
Checking the entry for 70:                                             
Key(s): 60

Java Code Editor:

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Java: Tips of the Day

Java Classes

A Java class is declared with the keywords public class along with a unique class name mirroring its file name. For example, in a file Hello.java in project helloworld:

package helloworld;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

 * @author seth
 * A GUI hello world.

public class Hello {
        // this is an empty class

You can declare variables and functions inside a class. In Java, variables within a class are called fields.

Ref: https://red.ht/3sL3sSl


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