Java: Get the first (lowest) key and the last (highest) key currently in a map
Write a Java program to get the first (lowest) key and the last (highest) key currently in a map.
Sample Solution:-
Java Code:
import java.util.*;
import java.util.Map.Entry;
public class Example9 {
public static void main(String args[]) {
// Create a tree map
TreeMap <String,String> tree_map1 = new TreeMap <String,String> ();
// Put elements to the map
tree_map1.put("C2", "Red");
tree_map1.put("C1", "Green");
tree_map1.put("C4", "Black");
tree_map1.put("C3", "White");
System.out.println("Orginal TreeMap content: " + tree_map1);
System.out.println("Greatest key: " + tree_map1.firstKey());
System.out.println("Least key: " + tree_map1.lastKey());
}
}
Sample Output:
Orginal TreeMap content: {C1=Green, C2=Red, C3=White, C4=Black} Greatest key: C1 Least key: C4
For more Practice: Solve these Related Problems:
- Write a Java program to retrieve the first key using firstKey() and the last key using lastKey() of a TreeMap and print them.
- Write a Java program to verify that the first key is the minimum and the last key is the maximum by comparing with a sorted list.
- Write a Java program to remove the first key using pollFirst() and then print the new first key of the TreeMap.
- Write a Java program to compare the results of firstKey() and lastKey() from two TreeMaps and output the difference.
Java Code Editor:
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