Skip to content
Related Articles

Related Articles

Improve Article

Set all the bits in given range of a number

  • Difficulty Level : Hard
  • Last Updated : 30 Apr, 2021

Given a non-negative number n and two values l and r. The problem is to set the bits in the range l to r in the binary representation of n, i.e, to unset bits from the rightmost lth bit to the rightmost r-th bit. 
Constraint: 1 <= l <= r <= number of bits in the binary representation of n.
Examples : 
 

Input : n = 17, l = 2, r = 3
Output : 23
(17)10 = (10001)2
(23)10 = (10111)2
The bits in the range 2 to 3 in the binary
representation of 17 are set.

Input : n = 50, l = 2, r = 5
Output : 62

 

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.

Approach: Following are the steps: 
 



1. Find a number 'range' that has all set
   bits in given range. And all other bits
   of this number are 0.
     range = (((1 << (l - 1)) - 1) ^ 
              ((1 << (r)) - 1));

2. Now, perform "n = n | range". This will 
   set the bits in the range from l to r 
   in n.

 

C++




// C++ implementation to Set bits in
// the given range
#include <iostream>
using namespace std;
 
// function to toggle bits in the given range
int setallbitgivenrange(int n, int l, int r)
{
    // calculating a number 'range' having set
    // bits in the range from l to r and all other
    // bits as 0 (or unset).
    int range = (((1 << (l - 1)) - 1) ^   
                ((1 << (r)) - 1));
 
    return (n | range);
}
 
// Driver code
int main()
{
    int n = 17, l = 2, r = 3;
    cout << setallbitgivenrange(n, l, r);
    return 0;
}

Java




// java implementation to Set bits in
// the given range
import java.util.*;
 
class GFG
{
     
    // function to toggle bits in the
    // given range
    static int setallbitgivenrange(int n,
                             int l, int r)
    {
         
        // calculating a number 'range'
        // having set bits in the range
        // from l to r and all other
        // bits as 0 (or unset).
        int range = (((1 << (l - 1)) - 1) ^
                    ((1 << (r)) - 1));
     
        return (n | range);
    }
     
    // Driver code
    public static void main(String[] args)
    {
        int n = 17, l = 2, r = 3;
         
        System.out.println(setallbitgivenrange(
                                      n, l, r));
    }
     
}
 
// This code is contributed by Sam007.

Python3




# Python3 implementation to Set
# bits in the given range
 
# Function to toggle bits
# in the given range
def setallbitgivenrange(n, l, r):
 
    # calculating a number 'range'
    # having set bits in the range
    # from l to r and all other
    # bits as 0 (or unset).
    range = (((1 << (l - 1)) - 1) ^
                ((1 << (r)) - 1))
 
    return (n | range)
 
# Driver code
n, l, r = 17, 2, 3
print(setallbitgivenrange(n, l, r))
 
# This code is contributed by Anant Agarwal.

C#




// C# implementation to Set
// bits in the given range
using System;
 
class GFG
{
    // function to toggle bits
    // in the given range
    static int setallbitgivenrange(int n, int l, int r)
    {
         
        // calculating a number 'range'
        // having set bits in the range
        // from l to r and all other
        // bits as 0 (or unset).
        int range = (((1 << (l - 1)) - 1) ^
                     ((1 << (r)) - 1));
     
        return (n | range);
    }
     
    // Driver code
    static void Main()
    {
        int n = 17, l = 2, r = 3;
        Console.Write(setallbitgivenrange(n, l, r));
    }
     
}
 
// This code is contributed by Sam007

PHP




<?php
// PHP implementation to Set
// bits in the given range
 
// function to toggle bits
// in the given range
function setallbitgivenrange($n, $l, $r)
{
    // calculating a number 'range'
    // having set bits in the range
    // from l to r and all other
    // bits as 0 (or unset).
    $range = (((1 << ($l - 1)) - 1) ^
                  ((1 << ($r)) - 1));
 
    return ($n | $range);
}
 
// Driver code
$n = 17;
$l = 2;
$r = 3;
echo setallbitgivenrange($n, $l, $r);
 
// This code is contributed by Sam007
?>

Javascript




<script>
 
// Javascript implementation to Set bits in
// the given range
 
// function to toggle bits in the given range
function setallbitgivenrange(n, l, r)
{
    // calculating a number 'range' having set
    // bits in the range from l to r and all other
    // bits as 0 (or unset).
    let range = (((1 << (l - 1)) - 1) ^   
                ((1 << (r)) - 1));
 
    return (n | range);
}
 
// Driver code
    let n = 17, l = 2, r = 3;
    document.write(setallbitgivenrange(n, l, r));
 
</script>

Output :  

23

This article is contributed by Devanshu Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
 




My Personal Notes arrow_drop_up
Recommended Articles
Page :