JavaScript/Bit-Manipulation/IsPowerOfTwo.js at master · TheAlgorithms/JavaScript · GitHub

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author: @Aayushi-Mittal

This script will check whether the given

number is a power of two or not.

A number will be a power of two if only one bit is set and rest are unset.

This is true for all the cases except 01 because (2^0 = 1) which is not a power of 2.

For eg: 10 (2^1 = 2), 100 (2^2 = 4), 10000 (2^4 = 16)

Reference Link: https://www.hackerearth.com/practice/notes/round-a-number-to-the-next-power-of-2/

If we will subtract 1 from a number that is a power of 2 we will get it's 1's complement.

And we know that 1's complement is just opp. of that number.

So, (n & (n-1)) will be 0.

For eg: (1000 & (1000-1))

1 0 0 0 // Original Number (8)

0 1 1 1 // After Subtracting 1 (8-1 = 7)

_______

0 0 0 0 // will become 0

export const IsPowerOfTwo = (n) => {

return n > 0 && (n & (n - 1)) === 0

}

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