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How to swap two bits in a given integer?

Last Updated : 23 Jul, 2025

Given an integer n and two-bit positions p1 and p2 inside it, swap bits at the given positions. The given positions are from the least significant bit (lsb). For example, the position for lsb is 0.
Examples: 

Input: n = 28, p1 = 0, p2 = 3
Output: 21
Explanation: 28 in binary is 11100.  If we swap 0'th and 3rd digits, we get 10101 which is 21 in decimal.

Input: n = 20, p1 = 2, p2 = 3
Output: 24


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Method 1: 
The idea is to first find the bits, then use XOR based swapping concept, i..e., to swap two numbers 'x' and 'y', we do x = x ^ y,  y = y ^ x, and x = x ^ y.

Below is the implementation of the above idea


Output
Result = 21 

Time Complexity: O(1)
Auxiliary Space: O(1)
 


Output
Result = 21

Time Complexity: O(1)
Auxiliary Space: O(1)

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