Number formed by the rightmost set bit in N
Given an integer N, the task is to find an integer M formed by taking the rightmost set bit in N i.e. the only set bit in M will be the rightmost set bit in N nd the rest of the bits will be unset.
Examples:
Input: N = 7
Output: 1
7 = 111, the number formed by the last set bit is 001 i.e. 1.Input: N = 10
Output: 2
10 = 1010 -> 0010 = 2Input: N = 16
Output: 16
Approach:
- Store x = n & (n – 1) which will unset the first set bit from the right in n.
- Now, update n = n ^ x to set the changed bit and unset all the others which is the required integer.
Below is the implementation of the above approach:
C++
// C++ implementation of the approach #include <bits/stdc++.h> using namespace std; // Function to return the integer formed // by taking the rightmost set bit in n int firstSetBit(int n) { // n & (n - 1) unsets the first set // bit from the right in n int x = n & (n - 1); // Take xor with the original number // The position of the 'changed bit' // will be set and rest will be unset return (n ^ x); } // Driver code int main() { int n = 12; cout << firstSetBit(n); return 0; } |
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Java
// Java implementation of the approach class geeks { // Function to return the integer formed // by taking the rightmost set bit in n public static int firstSetBit(int n) { // n & (n - 1) unsets the first set // bit from the right in n int x = n & (n-1); // Take xor with the original number // The position of the 'changed bit' // will be set and rest will be unset return (n ^ x); } // Driver Code public static void main (String[] args) { int n = 12; System.out.println(firstSetBit(n)); } } // This code is contributed by // sanjeev2552 |
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Python3
# Python3 implementation of the approach # Function to return the integer formed # by taking the rightmost set bit in n def firstSetBit(n): # n & (n - 1) unsets the first set # bit from the right in n x = n & (n - 1) # Take xor with the original number # The position of the 'changed bit' # will be set and rest will be unset return (n ^ x) # Driver code n = 12 print(firstSetBit(n)) # This code is contributed by mohit kumar 29 |
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C#
// C# implementation of the approach using System; class geeks { // Function to return the integer formed // by taking the rightmost set bit in n public static int firstSetBit(int n) { // n & (n - 1) unsets the first set // bit from the right in n int x = n & (n-1); // Take xor with the original number // The position of the 'changed bit' // will be set and rest will be unset return (n ^ x); } // Driver Code public static void Main () { int n = 12; Console.WriteLine(firstSetBit(n)); } } // This code is contributed by // anuj_67.. |
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Output:
4
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