w3resource

Java: Check whether an given integer is power of 2 or not using O(1) time

Java Basic: Exercise-205 with Solution

Write a Java program to check whether an integer is a power of 2 or not using O(1) time.

Note: O(1) means that it takes a constant time, like 12 nanoseconds, or two minutes no matter the amount of data in the set.
O(n) means it takes an amount of time linear with the size of the set, so a set twice the size will take twice the time. You probably don't want to put a million objects into one of these.

Visualization of powers of two from 1 to 1024:

Java Basic Exercises: Visualization of powers of two from 1 to 1024.

Sample Solution:

Java Code:

import java.util.*;
public class Main 
 {
 public static void main(String[] args)
  {
      boolean b = true;
      Scanner in = new Scanner(System.in);
      System.out.print("Input a number : ");
      int num = in.nextInt();           
     {   
     while(num!=1)
      {
        if(num%2!=0)
          { 
            b=! b;
            System.out.print(b);
            System.exit(0);
          }
            num = num / 2;
      }
       System.out.print(b);
     }
  }
         
}

Sample Output:

Input a number :  25
false

Flowchart:

Flowchart: Java exercises: Check whether an given integer is power of 2 or not using O(1) time.

Java Code Editor:

Contribute your code and comments through Disqus.

Previous: Compute xn % y where x, y and n are all 32bit integers.
Next: Generate a crc32 checksum of a given string or byte array.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Follow us on Facebook and Twitter for latest update.