Given a non-negative number n. The problem is to toggle the last m bits in the binary representation of n. A toggle operation flips a bit from 0 to 1 and a bit from 1 to 0.
Constraint: 1 <= m <= n.
Examples:
Input : n = 21, m = 2 Output : 22 (21)10 = (10101)2 (22)10 = (10110)2 The last two bits in the binary representation of 21 are toggled. Input : n = 107, m = 4 Output : 100
Approach: Following are the steps:
- Calculate num = (1 << m) – 1. This will produce a number num having m bits and all will be set.
- Now, perform n = n ^ num. This will toggle the last m bits in n.
C++
// C++ implementation to// toggle the last m bits#include <bits/stdc++.h>using namespace std;// function to toggle// the last m bitsunsigned int toggleLastMBits (unsigned int n, unsigned int m){ // calculating a number // 'num' having 'm' bits // and all are set. unsigned int num = (1 << m) - 1; // toggle the last m bits // and return the number return (n ^ num);}// Driver codeint main(){ unsigned int n = 107; unsigned int m = 4; cout << toggleLastMBits(n, m); return 0;} |
Java
// Java implementation to// toggle the last m bitsimport java.util.*;import java.lang.*;public class GfG{ // function to toggle // the last m bits public static int toggleLastMBits (int n, int m) { // calculating a number // 'num' having 'm' bits // and all are set int num = (1 << m) - 1; // toggle the last m bits // and return the number return (n ^ num); } // Driver function public static void main(String argc[]){ int n = 107; int m = 4; n = toggleLastMBits(n, m); System.out.println(n); }}// This code is contributed by Sagar Shukla. |
Python3
# Python implementation to# toggle the last m bits# function to toggle# the last m bitsdef toggleLastMBits(n,m): # calculating a number # 'num' having 'm' bits # and all are set. num = (1 << m) - 1 # toggle the last m bits # and return the number return (n ^ num)# Driver coden = 107m = 4print(toggleLastMBits(n, m))# This code is contributed# by Anant Agarwal. |
C#
// C# implementation to// toggle the last m bitsusing System;namespace Toggle{ public class GFG { // Function to toggle the last m bits public static int toggleLastMBits(int n, int m) { // Calculating a number 'num' having // 'm' bits and all are set int num = (1 << m) - 1; // Toggle the last m bits // and return the number return (n ^ num); } // Driver Code public static void Main() { int n = 107, m = 4; n = toggleLastMBits(n, m); Console.Write(n); } }}// This code is contributed by Sam007. |
PHP
<?php// PHP implementation to// toggle the last m bits // function to toggle // the last m bits function toggleLastMBits($n, $m) { // calculating a number // 'num' having 'm' bits // and all are set. $num = (1 << $m) - 1; // toggle the last m bits // and return the number return ($n ^ $num); }// Driver code{ $n = 107; $m = 4; echo toggleLastMBits($n, $m); return 0;}// This code is contributed by nitin mittal.?> |
Javascript
<script>// Javascript implementation to// toggle the last m bits// function to toggle// the last m bitsfunction toggleLastMBits(n, m){ // calculating a number // 'num' having 'm' bits // and all are set. var num = (1 << m) - 1; // toggle the last m bits // and return the number return (n ^ num);}// Driver codevar n = 107;var m = 4;document.write( toggleLastMBits(n, m));</script> |
Output:
100
Time Complexity : O(1)
Auxiliary Space: O(1)
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