1. Must be positive
Zero and negatives are never powers of two.
n > 0Typorithm · easy
Power of Two
▷ Interactive algorithm labpower-of-twobit-manipulationsingle-bitand-maskpositive-check
Saved on this device
Full lesson · 8 learning steps Open any exercise for focused practice
10%
Step 1 of 8 · intro card
Learn Power of Two
Bit Manipulation
A power of two has exactly one set bit, so n > 0 and n & (n-1) === 0 identifies it.
Powers of two are 1, 2, 4, 8... each with a single 1 bit in binary.
Clearing the lowest set bit of such a number leaves zero, since there is only one bit.
Guarding with n > 0 rules out zero and negatives.
Preparing algorithm lab…
01
Exactly one set bit.
02
n & (n-1) === 0 clears it to zero.
03
Require n > 0.
function isPowerOfTwo(n) {
return n > 0 && (n & (n - 1)) === 0;
}Read the implementation
Connect each part of the code to the concept before you type.
2. Single bit test
A power of two has exactly one set bit, so clearing it yields zero.
(n & (n - 1)) === 0A complete learning loop
01
Understand
Read the concept map and follow the code breakdown.
02
Reconstruct
Type the implementation, repair mistakes and work through every recall exercise.
03
Verify
Use the final check without hints; revisit weak concepts in short practice sessions.