Skip to content
Related Articles

Related Articles

Improve Article

Smallest power of 4 greater than or equal to N

  • Last Updated : 14 Apr, 2021

Given an integer N, the task is to find the smallest power of four greater than or equal to N.

Examples: 

Input: N = 12 
Output: 16 
24 = 16 which is the next required 
greater number after 12.

Input: N = 81 
Output: 81 
 

Approach:  



  1. Find the fourth root of the given n.
  2. Calculate its floor value using floor() function.
  3. If n is itself a power of four then return n.
  4. Else add 1 to the floor value.
  5. Return the fourth power of that number.

Below is the implementation of the above approach:  

C++




// C++ implementation of above approach
#include <bits/stdc++.h>
using namespace std;
 
// Function to return the smallest power
// of 4 greater than or equal to n
int nextPowerOfFour(int n)
{
    int x = floor(sqrt(sqrt(n)));
 
    // If n is itself is a power of 4
    // then return n
    if (pow(x, 4) == n)
        return n;
    else {
        x = x + 1;
        return pow(x, 4);
    }
}
 
// Driver code
int main()
{
    int n = 122;
    cout << nextPowerOfFour(n);
    return 0;
}

Java




// Java implementation of above approach
import java.util.*;
import java.lang.Math;
import java.io.*;
 
class GFG
{
     
// Function to return the smallest power
// of 4 greater than or equal to n
static int nextPowerOfFour(int n)
{
    int x = (int)Math.floor(Math.sqrt(Math.sqrt(n)));
 
    // If n is itself is a power of 4
    // then return n
    if (Math.pow(x, 4) == n)
        return n;
    else {
        x = x + 1;
        return (int)Math.pow(x, 4);
    }
}
 
// Driver code
public static void main (String[] args)
              throws java.lang.Exception
{
    int n = 122;
    System.out.println(nextPowerOfFour(n));
}
}
 
// This code is contributed by nidhiva

Python3




# Python3 implementation of above approach
import math
 
# Function to return the smallest power
# of 4 greater than or equal to n
def nextPowerOfFour(n):
    x = math.floor((n**(1/2))**(1/2));
 
    # If n is itself is a power of 4
    # then return n
    if ((x**4) == n):
        return n;
    else:
        x = x + 1;
        return (x**4);
 
# Driver code
 
n = 122;
print(nextPowerOfFour(n));
 
# This code is contributed by Rajput-Ji

C#




// C# implementation of above approach
using System;
class GFG
{
     
// Function to return the smallest power
// of 4 greater than or equal to n
static int nextPowerOfFour(int n)
{
    int x = (int)Math.Floor(Math.Sqrt(Math.Sqrt(n)));
 
    // If n is itself is a power of 4
    // then return n
    if (Math.Pow(x, 4) == n)
        return n;
    else
    {
        x = x + 1;
        return (int)Math.Pow(x, 4);
    }
}
 
// Driver code
public static void Main ()
{
    int n = 122;
    Console.WriteLine(nextPowerOfFour(n));
}
}
 
// This code is contributed by anuj_67..

Javascript




<script>
 
// Javascript implementation of above approach
 
// Function to return the smallest power
// of 4 greater than or equal to n
function nextPowerOfFour(n)
{
    let x = Math.floor(Math.sqrt(
            Math.sqrt(n)));
 
    // If n is itself is a power of 4
    // then return n
    if (Math.pow(x, 4) == n)
        return n;
    else
    {
        x = x + 1;
        return Math.pow(x, 4);
    }
}
 
// Driver code
let n = 122;
document.write(nextPowerOfFour(n));
 
// This code is contributed by mohit kumar 29
 
</script>
Output: 
256

 

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with experts, please refer DSA Live Classes for Working Professionals and Competitive Programming Live for Students.




My Personal Notes arrow_drop_up
Recommended Articles
Page :