LeetCode 190 Reverse Bits - Solution

Process one bit at a time. Extract the least significant bit from input, append it to the result.

For $32$ iterations: $1.$ Shift result left by 1 to make room. $2.$ Add the last bit of n to result (result |= n & 1). $3.$ Shift n right by 1 to move to the next bit.

This effectively reads bits right-to-left and writes them left-to-right.