1. All 32 bits
Process every bit of a 32-bit integer.
for (let i = 0; i < 32; i += 1)Typorithm · easy
Reverse Bits
▷ Interactive algorithm labreverse-bitsbit-manipulationshiftbuild-upunsigned
Saved on this device
Full lesson · 8 learning steps Open any exercise for focused practice
10%
Step 1 of 8 · intro card
Learn Reverse Bits
Bit Manipulation
Pull n's lowest bit and push it into result, shifting both, for all 32 bits.
Reversing bits builds the output one bit at a time from the input's low end.
Each step shifts result left to make room, then ORs in the lowest bit of n.
Using the unsigned shift >>> avoids JavaScript's signed 32-bit quirks.
Preparing algorithm lab…
01
Shift result left, OR in n & 1.
02
Use >>> for unsigned shifts.
03
Run exactly 32 times.
function reverseBits(n) {
let result = 0;
for (let i = 0; i < 32; i += 1) {
result = (result << 1) | (n & 1);
n = n >>> 1;
}
return result >>> 0;
}Read the implementation
Connect each part of the code to the concept before you type.
2. Shift in low bit
Make room in result, then append n's lowest bit.
result = (result << 1) | (n & 1)3. Drop low bit
Unsigned right shift discards the bit just read.
n = n >>> 14. Force unsigned
>>> 0 reinterprets the result as an unsigned 32-bit value.
return result >>> 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.